Systems and methods for providing an ion beam

ABSTRACT

Systems for generating a proton beam include an electromagnetic radiation beam (e.g., a laser) that is directed onto an ion-generating target by optics to form the proton beam. A detector is configured to measure a laser-target interaction property, which a processor uses to produce a feedback signal that can be used to alter the proton beam by adjusting the source of the electromagnetic radiation beam, the optics, or a relative position or orientation of the electromagnetic radiation beam to the ion-generating target. By adjusting the laser-target interaction, the feedback can be used to control properties of the proton beam, such as the proton beam energy or flux. Such systems have certain advantages, including reducing the size, complexity, and cost of machines used to generate proton beams, while also improving their speed, precision, and configurability.

The disclosed embodiments generally relate to improvements in ion beamgeneration, including proton beam generation, and particularly to ionbeam generation via interactions between an electromagnetic radiationbeam and an ion-generating target.

BACKGROUND

Aspects of this disclosure include many systems, subsystems, componentsand subcomponents. Background details already known are not repeatedherein. Such background information may include information contained inthe following materials:

-   -   U.S. Pat. No. 8,229,075 to Cowan et al., titled “Targets and        Processes for Fabricating Same,” issued Jul. 24, 2012;    -   U.S. Pat. No. 8,389,954 to Zigler et al., titled “System for        Fast Ions Generation and a Method Thereof,” issued Mar. 5, 2013;    -   U.S. Pat. No. 8,530,852 to Le Galloudec, titled “Micro-Cone        Targets for Producing High Energy and Low Divergence Particle        Beams,” issued Sep. 10, 2013;    -   U.S. Pat. No. 8,750,459 to Cowan et al., titled “Targets and        Processes for Fabricating Same,” issued Jun. 10, 2014;    -   U.S. Pat. No. 9,236,215 to Zigler et al., titled “System for        Fast Ions Generation and a Method Thereof,” issued Jan. 12,        2016;    -   U.S. Pat. No. 9,345,119 to Adams et al., titled “Targets and        Processes for Fabricating Same,” issued May 17, 2016; and    -   U.S. Pat. No. 9,530,605 to Nahum et al., titled “Laser Activated        Magnetic Field Manipulation of Laser Driven Ion Beams,” issued        Dec. 27, 2016.

Particle radio-therapy conducted with ions may be used to treat disease.In one form of particle therapy, called proton therapy, a tumor istreated by irradiating it with protons (e.g., hydrogen ions). Protontherapy has advantages over conventional photon-based therapies (e.g.,x-ray and gamma ray therapies) in part due to the way protons andphotons interact with a patient's tissue.

FIG. 1 shows the radiation dose as a function of tissue depth for bothphoton and proton therapies. Before a particle can irradiate thetreatment volume 106 defined by the patient's treatment plan, ittypically must traverse the patient's skin and other healthy tissuebefore reaching the treatment volume 106 of the patient. In doing so,the particles can damage healthy tissue, an undesirable side-effect ofthe treatment. As shown in curve 102 of FIG. 1, photons (e.g., x-rays)deliver most of their energy to the regions near the patient's skin. Fortumors deeper in the patient's body, this interaction may damage healthytissue. Additionally, some photons traverse the patient's body beyondthe treatment volume 106, irradiating yet more healthy tissue behind thetumor before ultimately exiting the other side of the patient's body.Although the radiation doses to these other healthy tissues is lowerthan the dose delivered near the patient's skin, it is stillundesirable.

Unlike photons, protons, exhibit a very desirable interaction with thepatient's tissue. As shown by curve 104 in FIG. 1, the peak interactionof protons with the patient's tissue occurs deeper within the patientand may cease abruptly after the peak interaction. Additionally, protonsinteract with surface tissues much less than photons, meaning that themajority of the proton beam's energy can be delivered to the treatmentvolume 106, and the irradiation of healthy tissue can be reduced. Takingadvantage of these benefits, proton therapy thus allows more preciseadministration of energy to unhealthy tissue in patients while avoidingdamage to healthy tissue. For example, proton therapy may reduce damageto surrounding healthy tissue by 2 to 6 times when compared to x-raytherapy, thereby improving patient survival and quality of life. Protonsmay reduce the lifetime risk of secondary cancer in children by 97%,compared to x-rays.

Commercial proton therapy centers are currently rare due todisadvantages in existing proton therapy systems, which generate protonbeams by using large and costly particle accelerators. Accelerator-basedsystems can be massive and are not scalable. As an example, FIG. 2 showsan approximate size comparison of an accelerator-based proton therapysystem against a football field. The energy requirements and maintenancecosts inherent in operating an accelerator-based system are alsoimmense. Taken together, these disadvantages lead to exorbitantconstruction and maintenance costs associated with proton therapy. Inaddition to the extravagant costs associated with accelerator-basedproton beam generation, adjusting certain properties of the proton beam(e.g., the beam energy and beam flux) can be cumbersome andtime-consuming in such systems. This leads to longer treatment times andlow patient throughput, further increasing the cost of individualtreatments as fewer patients share the cost burden. Accordingly, fewproton therapy centers currently exist, and patients often receiveinferior treatments due, in part, to unavailability of proton therapy.

The present disclosure is directed to alternative approaches to protontherapy. Although the embodiments disclosed herein contemplate themedical application of proton beam therapy, a person of ordinary skillin the art would understand that the novel proton beam generatingmethods and systems described below can be used in any application wherea proton beam is desired.

BRIEF SUMMARY OF EXEMPLARY DISCLOSED EMBODIMENTS

Some of the embodiments disclosed herein provide methods and systems forimproved generation of a proton beam. For example, disclosed embodimentsmay improve upon disadvantages of some conventional proton generationtechnologies, as described above, for example by providing improvedspeed, precision, and configurability, allowing proton beam generationto be performed more efficiently and at a lower cost. Disclosedembodiments may further reduce the size and complexity of existingsystems.

Consistent with the present embodiments, a system for generating aproton beam may include an interaction chamber configured to support anion-generating target; an electromagnetic radiation source configured toprovide an electromagnetic radiation beam; one or more optics componentsconfigured to direct the electromagnetic radiation beam at theion-generating target to thereby cause a resultant proton beam; adetector configured to measure at least one laser-target interactionproperty; and at least one processors configured to produce a feedbacksignal based on the at least one laser-target interaction propertymeasured by the detector and to alter the proton beam by adjusting atleast one of the electromagnetic radiation source, the one or moreoptics component, and at least one of a relative position andorientation of the electromagnetic radiation beam to the ion-generatingtarget.

Some embodiments may include a method including providing anelectromagnetic radiation beam; directing the electromagnetic radiationbeam at an ion-generating target within an interaction chamber tothereby cause a resultant proton beam; measuring at least onelaser-target interaction property; and producing a feedback signal basedon the at least one measured laser-target interaction property to alterthe proton beam by adjusting at least one of an electromagneticradiation source, one or more optics component, and at least one of arelative position and orientation of the electromagnetic radiation beamto the ion-generating target.

By way of example, the at least one laser-target interaction propertymay include a proton beam property (e.g., a proton beam energy or aproton beam flux).

A laser-target interaction property may include a secondary electronemission property, such as, for example, an x-ray emission property.

The electromagnetic radiation source may be configured to provide one ormore of a laser beam or, for example, a pulsed electromagnetic radiationbeam, for causing a pulsed proton beam.

The interaction chamber may include a target stage for supporting theion-generating target, and the at least one processor may be furtherconfigured to cause relative movement between the target stage and theelectromagnetic radiation beam.

A structure of the ion-generating target may be determined, at least inpart, for example, based upon a generated feedback signal generated froma measured laser-target interaction property.

Further, consistent with the present embodiments, the at least onelaser-target interaction property may include a proton beam energy.

Further, consistent with the present embodiments, the at least onelaser-target interaction property may include a proton beam flux.

Further, consistent with the present embodiments, the electromagneticradiation source may be configured to alter a temporal profile of theelectromagnetic radiation beam in response to the feedback signal.

Further, consistent with the present embodiments, the electromagneticradiation source may be configured to generate at least a main pulse anda pre-pulse, and the at least one processor may be configured to causethe electromagnetic radiation source to alter a contrast ratio of thepre-pulse to the main pulse in response to the feedback signal.

Further, consistent with the present embodiments, at least one processormay be configured to cause the electromagnetic radiation source to alteran energy of the electromagnetic radiation beam in response to thefeedback signal.

Further, consistent with the present embodiments, the one or moreprocessors may be configured to cause the electromagnetic radiationsource to alter a spatial profile of the electromagnetic radiation beam,for example by altering a spot size of the electromagnetic radiationbeam, in response to the feedback signal.

Further, consistent with the present embodiments, the at least oneprocessor may be configured to cause the one or more optics componentsto alter a spatial profile of the electromagnetic radiation beam, forexample by altering a spot size of the electromagnetic radiation beam inresponse to the feedback signal.

Further, consistent with the present embodiments, the at least oneprocessor may be configured to cause a motor to alter the relativeorientation between the electromagnetic radiation beam and theion-generating target in response to the feedback signal.

Another embodiment consistent with the present disclosures may comprisea system for generating a proton beam, the system comprising aninteraction chamber configured to support an ion-generating target; anelectromagnetic radiation source configured to provide anelectromagnetic radiation beam; an adaptive mirror configured to directthe electromagnetic radiation beam at the ion-generating target in theinteraction chamber to thereby generate a proton beam; and at least oneprocessor configured to control the adaptive mirror so as to adjust atleast one of a spatial profile of the electromagnetic radiation beam andat least one of a relative position and orientation between theelectromagnetic radiation beam and the ion-generating target.

Some embodiments may include a method including providing anelectromagnetic radiation beam; directing the electromagnetic radiationbeam, using an adaptive mirror, at an ion-generating target within aninteraction chamber to thereby cause a resultant proton beam;controlling the adaptive mirror with at least one processor so as toadjust at least one of a spatial profile of the electromagneticradiation beam and at least one of a relative position and orientationbetween the electromagnetic radiation beam and the ion-generatingtarget.

By way of example, the adaptive mirror may be configured to direct theelectromagnetic radiation beam by at least one of adjusting a focus ofthe electromagnetic radiation beam, diverting the electromagneticradiation beam, and scanning the electromagnetic radiation beam.

Further, consistent with the present embodiments, the adaptive mirrormay be configured to raster the electromagnetic radiation beam over theion-generating target.

Further, consistent with the present embodiments, the adaptive mirrormay comprise a plurality of facets, each of the plurality of facetsbeing independently controllable by digital logic circuitry.

Further, consistent with the present embodiments, the adaptive mirrormay comprise a laser pulse focused onto an anti-reflective coatedsubstrate, one or both of the laser pulse and anti-reflective coatedsubstrate being controllable by a digital logic circuitry.

Further, consistent with the present embodiments, the at least oneprocessor may be configured to cause the adaptive mirror to direct theelectromagnetic radiation beam at the ion-generating target in responseto a feedback signal.

Further, consistent with the present embodiments, the at least oneprocessor may be configured to cause the adaptive mirror to direct theelectromagnetic radiation beam at predetermined locations on a surfaceof the ion-generating target.

Further, consistent with the present embodiments, a surface of theion-generating target may include a patterned array.

Further, consistent with the present embodiments, a surface of theion-generating target may include a plurality of ion-generatingstructures substantially oriented along a common axis.

Further, consistent with the present embodiments, a surface of theion-generating target may include at least one knife edge.

Consistent with other disclosed embodiments, non-transitorycomputer-readable storage media may store program instructions, whichare executed by one or more processor devices and perform any of themethods described herein.

The foregoing general description is a brief summary of only a fewdisclosed embodiments, and is not intended to be restrictive of thenumerous inventive concepts set forth in the following drawings,detailed description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate certain aspects of the disclosedembodiments and, together with the description, explain the disclosedembodiments. In the drawings:

FIG. 1 is a graph depicting radiation dose correlated to tissue depth.

FIG. 2 is an approximate representation of size of some conventionalaccelerator-based particle therapy systems, as described above.

FIG. 3 is a diagram of an example of interconnected components of asystem for providing proton therapy, consistent with disclosedembodiments.

FIGS. 4A, 4B, 4C, 4D, and 4E are examples of ion-generating targets forproton beam generation, consistent with disclosed embodiments.

FIG. 5 is a schematic diagram of an example of a controller forcontrolling a proton therapy system, consistent with disclosedembodiments.

FIG. 6 is a schematic diagram of an example of an electromagneticradiation source, consistent with disclosed embodiments.

FIG. 7 is a schematic diagram of an example of a gantry, consistent withdisclosed embodiments.

FIG. 8 is a schematic diagram of another example of a gantry, consistentwith disclosed embodiments.

FIG. 9 is a flowchart of an example of a proton therapy process,consistent with disclosed embodiments.

FIG. 10 illustrates aspects of an example of an interaction chamber,consistent with disclosed embodiments.

FIG. 11 is a flowchart of an example of a process for controlling protontherapy with proton generation feedback, consistent with disclosedembodiments.

FIG. 12 depicts energy of an exemplary proton beam pulse consistent withdisclosed embodiments.

FIGS. 13A and 13B depict an example of a proton energy selection system,consistent with disclosed embodiments.

FIG. 14 is a flowchart of an example of a process for controlling protontherapy treatment in a three dimensional space, based on protongeneration feedback, consistent with disclosed embodiments.

FIGS. 15A, 15B, 15C, and 15D depict aspects of an exemplary protontherapy treatment based on the process of FIG. 14.

DETAILED DESCRIPTION

Reference is now made in detail to exemplary embodiments, examples ofwhich are illustrated in the accompanying drawings and disclosed herein.Wherever convenient, the same reference numbers are used throughout thedrawings to refer to the same or like parts.

Systems and methods are provided herein for providing ion beam therapy.The following embodiments are described in relation to proton therapy.As used here, “proton therapy” refers to a particle therapy medicalprocedure that uses a beam of protons to irradiate diseased tissue, mostoften in the treatment of cancer. While this description refers to thistherapeutic procedure, it is to be understood that the intended scope ofthe innovations herein are not limited to therapy or medical procedures.Rather, it may apply any time a proton beam is generated for anypurpose. In addition, the disclosure is not limited to the generation ofbeams of protons, but also applies to other forms of ion beamgeneration.

A system for generating a proton beam in accordance with the presentdisclosure may comprise one or more sources of electromagneticradiation. “Electromagnetic radiation,” as used in the presentdisclosure may refer to any form of electromagnetic radiation having anywavelength, frequency, energy, power, polarization, and/or spatial ortemporal profile. In some embodiments, electromagnetic radiation maypropagate in the form of a beam. For example, an electromagneticradiation beam may be any form of electromagnetic radiation suitable forirradiating a desired location. In some embodiments, a system forproviding proton therapy system may be configured to provide anelectromagnetic radiation beam along a trajectory. An electromagneticradiation beam may, for example, be configured for irradiating aplurality of patterned features on an ion-generating target (asdescribed in further detail below) or for irradiating one or more knifeedges on an ion-generating target (also described in further detailbelow).

An electromagnetic radiation beam may comprise a defined energy,wavelength, power, energy, polarization (or it may not be polarized),spatial profile, and/or temporal profile. Any of these traits may befixed or may vary. As an example, an electromagnetic radiation sourcemay be configured to provide a laser beam having traits tailored toproperties of an ion-generating target. An electromagnetic radiationbeam may be pulsed, to thereby cause a pulsed proton beam, or it may becontinuous to thereby cause a continuous proton beam.

A system for generating a proton beam in accordance with the presentdisclosure may comprise an ion-generating target. As used in the presentdisclosure, an ion-generating target may refer to any material,apparatus, or combination of elements configured for generating ions inresponse to electromagnetic irradiation. As described below, anion-generating target may be configured for generating a proton beam;however, a proton beam is merely an example. In some embodiments, anion-generating target may be provided with a plurality of patternedfeatures. For example, a plurality of patterned features may compriseprotrusions extending from a surface of an ion-generating target. Insome embodiments, an ion-generating target may patterned with one ormore knife edges. For example, a knife edge of an ion-generating targetmay include one or more narrow edges, similar to an arête or the edge ofa blade.

A system for generating a proton beam in accordance with the presentdisclosure may comprise optics component(s). As used in the presentdisclosure, optics component(s) may refer to any one or more componentsfor manipulating and/or controlling an electromagnetic radiation beam inany manner, including, for example, shaping, directing, filtering,splitting, delaying, modulating, absorbing, amplifying, focusing,chopping, and/or reflecting an electromagnetic radiation beam. As anexample, optics components may be positioned along a trajectory of anelectromagnetic radiation beam, for example between an electromagneticradiation source and a surface of an ion-generating target. In someembodiments, optics components may be configured to direct theelectromagnetic radiation beam at the ion-generating target, for exampleto thereby cause a resultant proton beam. Further, an electromagneticradiation source may include one or more optics components to facilitateformation of an electromagnetic radiation beam.

Consistent with the present disclosure, optics components may includeone or more adaptive mirror(s). As used in the present disclosure, anadaptive mirror may refer to an element that includes a reflectivesurface that may be adapted. For example, an adaptive mirror may be adeformable mirror that comprises a plurality of facets, each of theplurality of facets being independently controllable by a digital logiccircuitry. As another example, an adaptive mirror may be a plasma mirrorthat comprises a laser pulse focused onto an anti-reflective coatedsubstrate, one or both of the laser pulse and anti-reflective coatedsubstrate being controllable by a digital logic circuitry. In someembodiments, an adaptive mirror may be configured to direct anelectromagnetic radiation beam at an ion-generating target or, in someinstances, configured to cooperate with an electromagnetic radiationbeam to cause electromagnetic radiation beam to irradiate theion-generating target, thereby facilitating formation of a proton beam.An adaptive mirror in accordance with the present disclosure may beconfigured to adjust or control a spatial profile of an electromagneticradiation beam and/or to adjust or control at least one of a relativeposition and orientation between an electromagnetic beam and anion-generating target. In some instances, an adaptive mirror may beconfigured to direct an electromagnetic radiation beam by adjusting oneor more property of the electromagnetic radiation beam. For example,adjustment may be achieved by at least one of adjusting a focus of theelectromagnetic radiation beam, diverting the electromagnetic radiationbeam, and scanning the electromagnetic radiation beam.

Consistent with the present disclosure, a system for generating a protonbeam may be configured to raster an electromagnetic radiation beam, forexample over an ion-generating target. As used in the presentdisclosure, rastering may refer to a pattern of sequential scanning overa surface or volume having any shape. Rastering may, for example, beachieved by one or more motor configured to cause an electromagneticradiation beam to sequentially scan a surface or volume. In someembodiments, an electromagnetic radiation beam may be rastered overindividual patterned features of an ion-generating target or a knifeedge of an ion-generating target. In some embodiments, an adaptivemirror may be configured to direct an electromagnetic radiation beam tostrike individual features of an ion-generating target.

A system for generating a proton beam in accordance with the presentdisclosure may comprise proton beam adjustment component(s). As used inthe present disclosure, proton beam adjustment component(s) may refer toany one or more components for manipulating and/or controlling a protonbeam in any manner, including, for example, accelerating, analyzing,directing, shaping, filtering, splitting, delaying, modulating,absorbing, amplifying, focusing, chopping, and/or reflecting a protonbeam. For example, a proton beam adjustment component may include one ormore quadrupole lens, cylindrical mirror lens/analyzer (“CMA”),spherical mirror lens/analyzer (“SMA”), collimator, energy degrader,time-of flight control unit, magnetic dipole, or any other componentsuitable for manipulating charged ions.

A system for generating a proton beam in accordance with the presentdisclosure may be used in conjunction with a system for treating atreatment volume with protons. In the case of a medical treatment, thevolume may be a group of cells or an area of tissue. If employed outsidethe medical field, the volume may be any area or region for whichbenefit may be achieved through an application of radiation.

In accordance with the present disclosure, a gantry may be provided. Agantry may refer to any apparatus configured to assist in directingradiation toward a target. The target to be irradiated may be, forexample, a treatment volume such as a tumor within a patient's body.Because a system for treating a treatment volume with protons consistentwith the present disclosure is just one application of the disclosedsystems for generating a proton beam, it should be understood that thisis merely an example. A gantry may also be used to direct a proton beamor other radiation beam toward any target to be irradiated.

In accordance with the present disclosure, a patient support platformmay be provided. A patient support platform may refer to any surface,foundation, or other structure configured to support a patient duringirradiation therapy. A patient support platform may be fixed, or it maybe adjustable in any dimension.

Any of the systems in accordance with the present disclosure maycomprise at least one processor configured to monitor, control, and/orfacilitate the use of any component included in the system. Consistentwith the disclosed embodiments, a processor may refer to any one or moreprocessing devices, including, for example, an application specificintegrated circuit (ASIC), a digital signal processor (DSP), aprogrammable logic device (PLD), a field programmable gate array (FPGA),a controller, a microprocessor, or other similar electronic devicesand/or combinations thereof. A processor may comprise one or moremodules of a control system.

In some embodiments consistent with the present disclosure, at least oneprocessor may be configured to cause an electromagnetic radiation beamto strike individual patterned features that make up a plurality ofpatterned features an ion-generating target, and to thereby generate aresultant proton beam. In some embodiments consistent with the presentdisclosure, at least one processor may be configured to cause anelectromagnetic radiation beam to strike one or more knife edges of anion-generating target, and to thereby generate a resultant proton beam.

In some embodiments, at least one processor may control at least one ofan electromagnetic radiation source and/or optics components. Forexample, a processor or group of processors may control at least one ofthe energy of an electromagnetic radiation beam, the flux of anelectromagnetic radiation beam, the polarization of an electromagneticradiation beam, the spatial profile of an electromagnetic energy beam,the temporal profile of an electromagnetic radiation beam, or otheraspects of an electromagnetic radiation beam. More specifically, atleast one processor may generate instructions to cause anelectromagnetic radiation source to alter a spatial profile of anelectromagnetic radiation beam by altering a spot size of theelectromagnetic radiation beam. As another example, at least oneprocessor may alter a temporal profile of an electromagnetic radiationbeam by altering a chirp of the electromagnetic radiation beam. As afurther example, at least one processor may alter a temporal profile ofan electromagnetic radiation beam by altering a timing of one or morelaser pump sources.

In embodiments consistent with the present disclosure, at least oneprocessor may be configured to cause an adaptive mirror to direct anelectromagnetic radiation beam at predetermined locations on a surfaceof an ion-generating target. For example, a processor or processors maybe configured to cause an electromagnetic radiation beam to raster anion-generating target. Such rastering may include sequential scanning ofthe electromagnetic radiation beam over contiguous patterned featuresmaking up a plurality of patterned features. Striking the individualpatterned features may include, for example, continuously ordiscontinuously scanning a surface of an ion-generating target. In someembodiments, a processor may be configured to cause an adaptive mirrorto adjust an electromagnetic radiation beam so as to strike patternedfeatures individually, or it may be configured to strike individualpatterned features simultaneously.

In accordance with the present disclosure, at least one processor may beconfigured to control multiple aspects of a system independently orsimultaneously. For example at least one processor may be configured toadjust a flux of a proton beam while holding an energy of the protonbeam substantially constant, or may be configured to adjust an energy ofa proton beam while holding a flux of the proton beam substantiallyconstant. Alternatively, at least one processor may be configured toadjust a flux of a proton beam and an energy of a proton beamsimultaneously.

FIG. 3 depicts an exemplary system 300 for providing proton therapy thatincludes an illustrative system for generating a proton beam. System 300is also one example of a system for treating a treatment volume withprotons. In accordance with disclosed embodiments, system 300 mayinclude one or more of an electromagnetic radiation source 302, anion-generating target 304, optics component(s) 306, proton beamadjustment component(s) 308, a gantry 310, a patient support platform312, and a control system 314 configured to communicate with any one ormore of the above.

A patient may be positioned on patient support platform 312. Patientsupport platform 312 may be any shape or form suitable for use with theother components of system 300 and conducive to supporting a patientduring treatment. Patient support platform 312 may be fixed in placerelative to gantry 310, or patient support platform 312 may beconfigured for translation and/or rotation prior to or during treatment.In some embodiments patient support platform 312 may be adjusted toaccommodate patients of different sizes or to position a treatmentvolume in a path of a proton beam. Further, in some embodiments patientsupport platform 312 may be adjusted during treatment to reposition thetreatment volume relative to the proton beam.

Gantry 310 may be configured to direct the proton beam toward atreatment volume, such as a tumor, within the patient's body. Gantry 310may be configured to be manipulated in one or more ways to influence theproton beam's path, and may be composed of a number of materials andincorporate numerous components. Examples of gantry 310 consistent withembodiments of the disclosure are discussed in further detail below,which are not intended to be limiting.

Electromagnetic radiation source 302 may emit an electromagneticradiation beam 316, for example, a laser beam, directed towardion-generating target 304. In some embodiments, electromagneticradiation source 302 may comprise one or more gas lasers (e.g., CO2lasers), diode pumped solid state (DPSS) lasers (e.g., yitterbiumlasers, neodymium-doped yttrium aluminium garnet lasers (Nd:YAG), ortitanium-sapphire lasers (Ti:Sapphire)), and/or flash lamp pumped solidstate lasers (e.g., Nd:YAG or neodymium glass). In a broader sense, anyradiation source capable of causing a release of ions from a target maybe employed.

An electromagnetic radiation source 302 may be selected based on itsintensity, i.e. the energy divided by the temporal duration of the pulseand the spot size of the laser on the ion-generating target 304. Avariety of combinations of spatial profile (e.g., spot size),wavelength, temporal duration, and energy may be used while stillproviding the same intensity. For example, in some embodiments,electromagnetic radiation beam 316 may be within an energy range of 1 Jto 25,000 J, and a wavelength range of 400 nm to 10,000 nm.Electromagnetic radiation beam 316 may be pulsed, for example with apulse width range of 10 fs to 100 ns. Electromagnetic radiation beam 316may have various spot sizes. In some embodiments, a spot size between 1μm² and 1 cm² may be used. Although spatial profiles of electromagneticradiation beam 316 may have any beam profile, in some embodiments thespatial profile may include a Gaussian, super-Gaussian, Top Hat, Bessel,or annular beam profile.

In some embodiments, electromagnetic radiation source 302 may beconfigured to generate a main pulse after one or more pre-pulses.Contrast ratio (i.e., the ratio between the main pulse and thepre-pulses, also called a “pedestal” arriving before the main pulse) mayinfluence proton generation. Contrast ratio may be more specificallydefined the higher the intensity of the laser. As an example, on atimescale shorter than 100 ps, contrast ratio may range from 10⁻⁸ to10⁻¹².

As a more specific example, electromagnetic radiation source 302 may bea Ti:Sapphire laser. In the example of the Ti:sapphire laser,electromagnetic radiation beam 316 may be within an energy range ofabout 1 J to 25 J, and have a wavelength of about 800 nm. In thisexample, electromagnetic radiation beam 316 may have a pulse width rangeof about 10 fs to 400 fs, a spot size between about 2 μm² and 1 mm², anda Gaussian or Top Hat spatial profile. These properties are merelyexemplary, and other configurations may be employed.

Electromagnetic radiation beam 316 may be directed to ion-generatingtarget 304 by one or more optics component(s) 306 disposed, for example,along a trajectory between electromagnetic radiation source 302 andion-generating target 304. Optics component(s) 306 may include one ormore optical and/or mechanical components configured to alter propertiesof electromagnetic radiation beam 316, including spectral properties,spatial properties, temporal properties, energy, polarization, contrastratio, or other properties. Optics component(s) 306 may be involved, forexample, in generating, optimizing, steering, aligning, modifying, andor measuring electromagnetic radiation beam 316, or in other aspects ofsystem 300. Optics component(s) 306 may include a wide variety ofoptical elements, such as lenses, mirrors, laser crystals and otherlasing materials, piezo activated mirrors, plates, prisms, beamsplitters, filters, light pipes, windows, blanks, optical fibers,frequency shifters, optical amplifiers, gratings, pulse shapers, XPW,Mazzler (or Dazzler) filters, polarizers, Pockels cells, opticalmodulators, apertures, saturable absorbers, and other optical elements.

Optics component(s) 306 may be fixed or adaptive. For example, opticscomponent(s) 306 may include one or more active, adaptive, orreconfigurable components, such as deformable mirrors, plasma mirrors,Pockels cells, phase shifters, optical modulators, irises, shutters(manually and computer controlled), and other similar components.Adaptive properties may manipulate optic components themselves, as inthe case of a deformable mirror or plasma mirror. The orientation ofoptics component(s) 306 may also be adjustable, such as by translatingoptics component(s) 306 or rotating optics component(s) 306 about arotational axis. Adjustments may be manual or automated. As one example,control system 314 may receive a feedback signal and, in response,provide a control signal to a motor connected to optics component(s) 306located between electromagnetic radiation beam 316 and theion-generating target 304. Movement of the motor, in turn, may adjustoptics component(s) 306 to alter the relative orientation betweenelectromagnetic radiation beam 316 and the ion-generating target 304(e.g., by repositioning the location of the laser-target interaction).

Examples of deformable mirrors that may be employed in opticscomponent(s) 306 include, for example, segmented mirrors, continuousfaceplate mirrors, magnetic mirrors, MEMS mirrors, membrane mirrors,bimorph mirrors, and/or ferrofluidic mirrors. Any number of other mirrortechnologies capable of altering the wave front of an electromagneticradiation beam may also be used.

Examples of plasma mirrors that may be employed in optics component(s)306 include a laser pulse focused onto an anti-reflective coatedsubstrate, which ionizes so as to reflect and separate a high intensitypeak from a lower intensity background of the pulse. As an example, aplasma mirror may be established by directing the laser pulse towards aparabolic mirror located in front of the anti-reflective coatedsubstrate. Other ways of implementing a plasma mirror are also known tothose of ordinary skill in the art, and are suitable for use withembodiments of the systems and methods described herein.

Optics component(s) 306 may be tailored to parameters related to anintended beam. For example, optics components 306 may be tailored interms of wavelength, intensity, temporal pulse shape (e.g., pulsewidth), spatial size and energy distribution, polarization, and otherproperties of the intended beam. Such beam parameters may relate to anoptics substrate material, size (e.g., lateral size or thickness),coating material (if any), shape (e.g., planar, spherical or other),orientation relative to a beam, or other specifications.

Optics component(s) 306 may include one or more corresponding holdersconfigured to hold the element in place while allowing positioning ofthe element to an appropriate degree of accuracy, for exampletranslation and rotation, as well as other degrees of freedom. In anembodiment, such holders may include opto-mechanical mounts held inplace by an optical table or any other mechanical holder. Such degreesof freedom may be manipulated manually or via any appropriate automaticmeans, such as electric motors.

Optics component(s) 306 may be disposed in specific environmentalconditions, such as a vacuum and/or an environment purged by one or moregasses. Furthermore, optics components 306 may be disposed in variousplaces along the path of electromagnetic radiation source 302 betweenelectromagnetic radiation source 302 and ion-generating target 304, orin any other system of system 300 where optical components are desired.Optics component(s) 306 may be configured for various uses, such aslaser beam steering, laser beam diagnostics, laser-target interactiondiagnostics, and/or ion-generating target viewing and positioning.

In some embodiments, the lifespan of optics component(s) 306 may vary.Some optics component(s) 306 may be long-term equipment, reused numeroustimes. Alternatively or additionally, some optics component(s) 306 maybe consumable, used fewer times and replaced. Such classification may bebased on a number of factors such as laser intensity and presence ofdebris/contamination. In some embodiments debris shielding may beinstalled proximate expensive or delicate optics to reduce a need forfrequent replacements. Periodic examination may be performed for opticssuspected to be damaged. Specialized optical systems may be installed toexamine optics at risk.

Optics component(s) 306 may be manipulated manually, automatically, orby any combination thereof. Input types for manipulating opticscomponents 306 may include high voltage signals, triggering signals,optical pumping, or any other form of input. Further, optics components306 may be monitored by one or more cameras, such as CCD cameras.Automatic manipulation of adaptive mirror(s) may occur, for example, inresponse to one or more signals provided by the control system 314. Thecontrol system 314 may, for example, control one or more motor(s),piezoelectric element(s), microelectromechanical (MEMS) element(s),and/or the like associated with a deformable mirror. Alternatively oradditionally, the control system 314 may, for example, control one ormore laser pulse(s), anti-reflective coated substrate(s), and/or thelike associated with a plasma mirror.

In some embodiments, optics component(s) 306 may include an adaptivedeformable mirror, such as a deformable mirror having a plurality offacets, each of the plurality of facets being independentlycontrollable. The facets may be controlled by digital control logiccircuitry, such as digital control logic circuitry contained in controlsystem 314. As another example, an adaptive mirror may be a plasmamirror that uses a focused laser pulse to ionize an anti-reflectivecoated substrate, thereby reflecting and separating a high intensitypeak from a lower intensity background of the laser pulse. The laserpulse and/or anti-reflective coated substrate may be controlled bydigital control logic circuitry, such as digital control logic circuitrycontained in control system 314.

An adaptive mirror may be configured to direct the electromagneticradiation beam 316 by one or more of adjusting a focus of theelectromagnetic radiation beam, diverting the electromagnetic radiationbeam, and scanning the electromagnetic radiation beam. The adaptivemirror may be configured to adjust focus of electromagnetic radiationbeam in any way apparent to those of skill in the art. For example,electromagnetic radiation beam 316 may strike a plurality of facets of adeformable mirror, or electromagnetic radiation beam 316 may strike aplasma mirror. In some configurations, it may be desirable to adjustwhere electromagnetic radiation beam 316 is directed or to adjust aproperty of the electromagnetic radiation beam 316. A plurality offacets of a deformable mirror may be controlled to reflectelectromagnetic radiation beam 316 such that its spot size at a desiredlocation is smaller, larger, or differently shaped than its spot sizejust before striking the deformable mirror. Likewise, a plasma mirrormay be controlled to reflect electromagnetic radiation beam 316 suchthat its spot size at a desired location is smaller, larger, ordifferently shaped than its spot size just before striking the plasmamirror.

The adaptive mirror may also be configured to divert electromagneticradiation beam 316. For example, system 300 may be configured such thatelectromagnetic radiation beam 316 will sequentially or simultaneouslystrike a plurality of locations on ion-generating target 304 or aplurality of ion-generating targets 304 disposed in different locationswithin system 300. In such configurations, an adaptive mirror or otheroptics component(s) 306 may alter the path of electromagnetic radiationbeam 316 to direct the beam onto the multiple locations and/or pluralityof ion-generating targets. For example, an adaptive mirror or otheroptics component(s) 306 may sequentially divert (e.g., scan)electromagnetic radiation beam 316 from one location to an adjacentlocation in a pattern continuously or discontinuously, such as in astepwise manner. In an automated process, control system 314 may beconfigured to cause the adaptive mirror to direct electromagneticradiation beam 316 at predetermined locations on the surface ofion-generating target 304. For example, it may be advantageous to scanelectromagnetic radiation beam 316 over a patterned array ofion-generating features provided at a surface of ion-generating target304. It may also be advantageous to scan electromagnetic radiation beam316 over an ion-generating target 304 that includes a plurality ofion-generating structures substantially oriented along a common axis,such as protrusions substantially extending away from a surface of theion-generating target 304. It may also be advantageous to scanelectromagnetic radiation beam 316 over an ion-generating target 304patterned with one or more knife edges, such as an ion-generating targetthat includes one or more features having a narrow edge similar to anarête or the edge of a blade. The adaptive mirror is described as anexample. Those of skill in the art will recognize that other opticscomponent(s) 306 may perform the same or similar functions as thosedescribed above in reference to the adaptive mirror.

In accordance with the present disclosure, an ion-generating target maybe configured to facilitate ion generation. For example, anion-generating target may include a surface having one or moreion-generating structures or features. Such structures or features maybe composed of one or more suitable materials, including ice (alsoreferred to as snow), plastic, silicon, stainless steel or any of avariety of metals, carbon and/or any other material from which an ionbeam may be generated. Such structures may be randomly arranged,arranged as defined by a growth or deposition process, and/or arrangedin a patterned array. Such structures may alternatively or additionallyinclude one or more narrow edges, similar to an arête or the edge of ablade. The structures may be configured based on one or more attributesof an electromagnetic radiation beam. For example, such structures mayhave a dimension smaller than a wavelength of an electromagneticradiation beam, such as a laser.

Ion-generating target 304, when struck by electromagnetic radiation beam316, may emit a variety of particles, including electrons, protons,x-rays, and other particles. Ion-generating target 304 may be composedof a variety of materials. Ion-generating target 304 may be configuredsuch that it includes one or more individual features configured tointeract with electromagnetic radiation beam 316. Alternatively oradditionally, ion-generating target 304 may include a continuous surfaceor texture formed from a material favorable for interaction withelectromagnetic radiation beam 316. Those of skill in the art willunderstand that there are numerous configurations that may be employedto emit particles upon interaction with an electromagnetic radiationbeam, and that the disclosed embodiments are merely exemplary.

In some embodiments, ion-generating target 304 may be prefabricated. Inother embodiments, ion-generating target 304 may be produced in situwithin system 300 or an attached sample preparation system. For example,ion-generating target 304 may disposed within an interaction chamber,such as interaction chamber 1000, described below. This may involveforming an ion-generating target from a suitable material, includingforming such material on a substrate. Such materials may include anygas, solid, or liquid chemical sources of the types commonly known intechniques such as evaporation, physical vapor deposition, chemicalvapor deposition, molecular beam epitaxy, atomic layer deposition, andthe like. For example, in embodiments in which ion-generating target 304includes ice, materials used to form ion-generating targets may includewater vapor (H₂O), hydrogen gas (H₂), and/or oxygen gas (O₂). Further,in embodiments in which ion-generating target 304 includes silicon,materials used to form ion-generating target 304 may include, forexample, silane (SiH₄), disilane (Si₂H₆), trichlorosilane (SiHCl₃), orany other silicon source. Further still, in embodiments in whichion-generating target 304 includes plastic, sources may include, forexample, polytetrafluoroethylene (PTFE) polymer source materials or anyother PTFE source. As a person of ordinary skill in the art wouldrecognize, these are just a few illustrative examples among manyavailable target materials and target source materials. In addition, theinteraction chamber may vary in structure to suit the form of the targetemployed. For example, when the target is ice, the interaction chambermay be specifically configured to maintain an appropriate temperature tosupport the ice. Each target material may have differing sustainingrequirements, and therefore the structure of the interaction chamber mayvary to suit the target.

FIG. 4. depicts illustrative ion-generating targets that may be employedas ion-generating target 304. For example, FIG. 4A shows anion-generating target 402 including a cap structure 404 located over ahollow, hourglass-shaped cone 406. In one embodiment, a distance betweenat least two opposing points of the cone may be less than about 15 μm.In particular examples, the distance may be less than about 1 μm. Insome embodiments, the features of ion-generating target 402 may be freestanding. Such features may include, for example, any number of shapes,including cones, pyramids, hemispheres, and capped structures. Thestructures of illustrative ion-generating target 402 shown in FIG. 4 (aswell as other embodiments of ion-generating target 304) may be formedusing lithographic techniques, such as photolithographic techniques. Inparticular examples, an ion-generating target cone 406 may be fabricatedon a silicon wafer 408, then coated with one or more metals 410. In someembodiments, protons may be ejected from a back-side opening 412. FIG.4B depicts another illustrative ion-generating target suitable asion-generating target 304 for use with the present invention. FIG. 4Bdepicts a portion of an ion-generating target having one or moremicro-cone targets 420 on its surface. Each micro-cone target 420 may besuitable for producing a high energy, low divergence particle beam. Inone embodiment, the micro-cone target 420 may include a substantiallycone-shaped body 422 having an outer surface 424, an inner surface 426,a generally flat and round, open-ended base 428, and a tip 430 definingan apex. The cone-shaped body 422 may taper along its length from thegenerally flat and round, open-ended base 428 to tip 430, which definesthe apex. Outer surface 424 and inner surface 426 may connect base 428to tip 430.

FIGS. 4C, 4D, and 4E depict other illustrative ion-generating targets304 suitable for use with embodiments of the present invention.Specifically, FIGS. 4C, 4D, and 4E depict surfaces of snow targets,which may be formed from crystals of ice. Ice may be advantageous foruse as an ion-generating target because water is rich in hydrogen.Further, as shown in FIG. 4C, structures on the ion-generating targetmay exhibit a needle-like shape. Such a shape may enhance an electricalfield generated by interaction of electromagnetic radiation beam 316 andion-generating target 304. Individual needle-like structures onion-generating target 304 may be approximately the same as a wavelengthof electromagnetic radiation beam 316. As an example, structures may beapproximately 1 μm to 10 μm.

Individual patterned features on the surface of ion-generating target304 may be physically arranged on ion-generating target 304 such thatthey may be sequentially scanned. For example, such structures may bearranged in an array on a generally planar surface. Individualstructures may be distributed evenly forming a pattern across an entiresurface, as shown in FIG. 4C. Alternatively, structures may be arrangedin a repeating pattern with space between the structures, as shown inFIGS. 4D and 4E.

Referring back to FIG. 3, proton beam adjustment component(s) 308 mayinclude one or more components configured to form a proton beam 318 fromprotons generated by ion-generating target 304 and to direct the protonbeam to gantry 310 and the treatment volume in the patient. Proton beamadjustment components 308 may include any equipment capable ofmanipulating charged particles, such as protons. For example, protonbeam adjustment component(s) 308 may include electromagnetic components.More specifically, proton beam adjustment component(s) 308 may includeone or more electromagnetic constituents, such as a quadrupole lens,cylindrical mirror lens/analyzer (“CMA”), spherical mirror lens/analyzer(“SMA”), collimator, energy degrader, time-of flight control unit,magnetic dipole, or any other component suitable for manipulatingcharged ions. Proton beam adjustment component(s) 308 may also adjustone or more properties of the proton beam 318. For example, beamadjustment components 308 may manipulate properties such as flux or spotsize. Proton beam adjustment component(s) 308 may also filter particleshaving particular energies or reduce the energy of various particles.

Proton beam adjustment component(s) 308 may be disposed in variouslocations within system 300, including inside an interaction chamber,along a proton beam line, within gantry 310, or any combination thereof.For example, proton beam adjustment components may be disposed along abeam line extending between ion-generating target 304 and gantry 310.The beamline may be configured to maintain various conditions such astemperature, pressure (e.g., vacuum), or other condition(s) conducive topropagating and/or manipulating proton beam 318. The beam line mayfurther include other components for housing charged particle beams,including, but not limited to, elements such as beam dumps, beamattenuators, and protective shielding.

Control system 314 may monitor and/or control various aspects of system300. For example, control system 314 may monitor various detectorsassociated with electromagnetic radiation source 302, opticscomponent(s) 306, ion-generating target 304, proton beam adjustmentcomponent(s) 308, gantry 310, and/or patient support platform 312.Control system 314 may also accept input from a user of system 300, suchas a technician or other operator. Control system 314 may also accept,store, and execute operations pertaining to system 300, including, forexample, initiating and maintaining any functionalities of system 300.Control system 314 may also be configured to implement feedback betweenone or more detectors and one or more of the various components ofsystem 300. For example, such feedback may improve precision,efficiency, speed, and/or other aspects of system 300 or its operation.Examples of such feedback are described in greater detail below.

FIG. 5 is a diagram of an exemplary computing system 500, illustrating aconfiguration that may be associated with control system 314 andconsistent with disclosed embodiments. As a person of ordinary skillwill understand, some or all of the functions associated with controlsystem 314 may be executed or facilitated by software, hardware, or anycombination thereof, associated with computing system 500. In oneembodiment, computing system 500 may have one or more processors 520,one or more memories 540, and one or more input/output (I/O) devices530. In some embodiments, computing system 500 may take the form of aserver, general purpose computer, customized dedicated computer,mainframe computer, laptop, mobile device, or any combination of thesecomponents. In certain embodiments, computing system 500 (or a systemincluding computing system 500) may be configured as a particularapparatus, system, or the like based on the storage, execution, and/orimplementation of software instructions that may perform one or moreoperations consistent with the disclosed embodiments. Computing system500 may be standalone, or it may be part of a subsystem, which may bepart of a larger system.

Processor 520 may include one or more known processing devices, such asan application specific integrated circuit (ASIC), a digital signalprocessor (DSP), a programmable logic device (PLD), a field programmablegate array (FPGA), a processor, a controller, a microprocessor, otherelectronic units and combination thereof. For example processor 520 mayinclude a processor from the Pentium™ or Xeon™ family manufactured byIntel™, the Turion™ family manufactured by AMD™, or any of variousprocessors manufactured by Sun Microsystems. Processor 520 mayconstitute a single core or multiple core processor that executesparallel processes simultaneously. For example, processor 520 may be asingle core processor configured with virtual processing technologies.In certain embodiments, processor 520 may use logical processors tosimultaneously execute and control multiple processes. Processor 520 mayimplement virtual machine technologies, or other known technologies toprovide the ability to execute, control, run, manipulate, store, etc.multiple software processes, applications, programs, etc. Processor 520may include a multiple-core processor arrangement (e.g., dual, quadcore, etc.) configured to provide parallel processing functionalities toallow computing system 500 to execute multiple processes simultaneously.One of ordinary skill in the art would understand that other types ofprocessor arrangements could be implemented that provide for thecapabilities disclosed herein. The disclosed embodiments are not limitedto any type of processor(s).

Memory 540 may include one or more storage devices configured to storeinstructions used by processor 520 to perform functions related to thedisclosed embodiments. For example, memory 540 may be configured withone or more software instructions, such as program(s) 550 that mayperform one or more operations when executed by processor 520. Thedisclosed embodiments are not limited to separate programs or computersconfigured to perform dedicated tasks. For example, memory 540 mayinclude a program 550 that performs the functions of computing system500, or program 550 could comprise multiple programs. Additionally,processor 520 may execute one or more programs located remotely fromcomputing system 500. For example, controller 314, may, via computingsystem 500 (or variants thereof), access one or more remote programsthat, when executed, perform functions related to certain disclosedembodiments. Processor 520 may further execute one or more programslocated in a database 570. In some embodiments, programs 550 may bestored in an external storage device, such as a server located outsideof computing system 500, and processor 520 may execute programs 550remotely.

Memory 540 may also store data that may reflect any type of informationin any format that the system may use to perform operations consistentwith the disclosed embodiments. Memory 540 may store instructions toenable processor 520 to execute one or more applications, such as serverapplications, network communication processes, and any other type ofapplication or software. Alternatively, the instructions, applicationprograms, etc., may be stored in an external storage (not shown) incommunication with computing system 500 via a suitable network,including a local area network or the internet. Memory 540 may be avolatile or non-volatile, magnetic, semiconductor, tape, optical,removable, non-removable, or other type of storage device or tangible(i.e., non-transitory) computer-readable medium.

Memory 540 may include data 560. Data 560 may include any form of dataused by controller 314 in controlling ion (e.g., proton) therapytreatment via system 300. For example, data 560 may include data relatedto operation of various components of system 300, feedback parametersassociated with various components of operating system 300, datagathered from one or more detectors associated with system 300,treatment plans for particular patients or for particular diseases,calibration data for various components of system 300, etc.

I/O devices 530 may include one or more devices configured to allow datato be received and/or transmitted by computing system 500. I/O devices530 may include one or more digital and/or analog communication devicesthat allow computing system 500 to communicate with other machines anddevices, such as other components of system 300 shown in FIG. 3. Forexample, computing system 500 may include interface components, whichmay provide interfaces to one or more input devices, such as one or morekeyboards, mouse devices, displays, touch sensors, card readers,biometric readers, cameras, scanners, microphones, wirelesscommunications devices, and the like, which may enable computing system500 to receive input from an operator of controller 314. Further, I/Odevices may include one or more devices configured to allow controlsystem 314 to communicate with one or more of the various devices ofsystem 300, such as through wired or wireless communication channels.

Computing system 500 may also contain one or more database(s) 570.Alternatively, computing system 500 may be communicatively connected toone or more database(s) 570. Computing system 500 may be communicativelyconnected to database(s) 570 via a network such as a wired or wirelessnetwork. Database 570 may include one or more memory devices that storeinformation and are accessed and/or managed through computing system500.

FIG. 6 is a general schematic of an exemplary electromagnetic radiationsource 302. As shown in FIG. 6, electromagnetic radiation source 302 mayinclude one or more oscillators 602, pump sources 604, optics components606, diagnostics components 608, stretchers 610, amplifiers 612,compressors 614, and controllers 616. The configuration of FIG. 6 ismerely an example, and numerous other configurations may be implementedconsistent with the disclosed embodiments, incorporating one or more ofthe components of electromagnetic radiation source 302, system 300, orother components.

Oscillator 602 may include one or more lasers for generating an initiallaser pulse 618 to be manipulated (e.g., shaped and/or amplified) toreach requirements for electromagnetic radiation beam 316. A widevariety of lasers or laser systems may be used as oscillator 602,including commercial available laser systems.

Pump source 604 may include independent lasers or laser system(s)configured to transfer energy into laser pulse 618. In some embodiments,pump source 604 may be connected to the output of oscillator 602 by anoptical beamline incorporating one or more of optics component(s) 306.Additionally or alternatively, pump source 604 may include other pumpmechanisms such as flash lamps, diode lasers, and diode-pumpedsolid-state (DPSS) lasers, or the like. In some embodiments, pump source604 may be configured to alter a temporal profile of electromagneticradiation beam 316. For example, control system 314 may be configured tocontrol a timing of pump source 604, thereby controlling the timing of apre-pulse and a pedestal of the electromagnetic radiation beam.

Optics components 606 may include any of the components discussed inrelation to optics components 306, and may perform any of the rolesand/or functions described in relation to optics components 306.

Diagnostics 608 may include optical, opto-mechanical, or electroniccomponents designed to monitor laser pulse 618, such as, for example itstemporal and spatial properties, spectral properties, timing, and/orother properties. More specifically, diagnostics 608 may include one ormore photodiodes, oscilloscopes, cameras, spectrometers, phase sensors,auto-correlators, cross-correlators, power meters or energy meters,laser position and/or direction sensors (e.g., pointing sensors),dazzlers (or mazzlers), etc. Diagnostics 608 may also include orincorporate any of the components identified above with respect tooptics components 606.

Stretcher 610 may be configured to chirp or stretch laser pulse 618.More specifically, stretcher 610 may include diffraction grating(s) orother dispersive components, such as prisms, chirped mirrors, and thelike.

Amplifier 612 may comprise an amplification medium such as, for example,titanium sapphire crystal, CO₂ gas, or Nd:YAG crystal. Amplifier 612 mayalso include a holder for the amplification medium. The holder may beconfigured to be compatible with supporting environmental conditionssuch as positioning, temperature, and others. Amplifier 612 may beconfigured to receive energy from pump source 604 and transfer thisenergy to laser pulse 618.

Compressor 614 may include an optical component configured to compresslaser pulse 618 temporally, for example to a final temporal duration.Compressor 614 may be constructed from diffraction gratings positionedon holders and positioned in a vacuum chamber. Alternatively, compressor614 may, for example, be constructed of dispersion fibers or prisms. Inaddition, the compressor 614 may include mirrors or other opticscomponents 306, as well as motors, and other electronically controlledopto-mechanics.

Controller 616 may include electronic system(s) that control and/orsynchronize various components of electromagnetic radiation source 302.Controller 616 may include any combination of controllers, powersupplies, computers, processors, pulse generators, high voltage powersupplies, and other components. As an example, controller 616 mayinclude one or more computing systems 500, which may be dedicated toelectromagnetic radiation source 302 or shared with other components ofsystem 300. In some embodiments, some or all of the functions ofcontroller 616 may be performed by controller 314 of system 300.

Controller 616 may interface with various components of electromagneticradiation source 302 and other components of system 300 via variouscommunication channels. The communication channels may be configured totransmit electrical or other signals to control various optical andopto-mechanical components associated with radiation source 302 orsystem 300. The communication channels may include a conductorcompatible with high voltage, electrical triggers, various wired orwireless communication protocols, optical communications, and othercomponents. Controller 616 may receive input from optical and mechanicaldiagnostics along electromagnetic radiation source 302, and fromdiagnostics 608 along other parts of system 300. Further, controller 616may receive signals from or based on input from a user, for examplesignals based on a patient treatment plan input by a user.

FIG. 7 depicts an example of a gantry 700, consistent with embodimentsof the present disclosure. In some embodiments, gantry 310 (FIG. 3) maybe arranged in the form of gantry 700, although this is not intended tobe limiting, and other gantry designs may be employed. Gantry 700 maydeliver proton beam 318 to an isocenter 712. In some embodiments,isocenter 712 may represent the location of a treatment volume or alocation within a treatment volume. Gantry 700 may also be configuredfor beam adjustment and reconfiguration for appropriately directingproton beam 318 prior to and during a treatment. Gantry 700 may includea solenoid 704, a coupling 706, beam adjustment component(s) 708,collimator(s) 718, and scanning magnet(s) 710. Height 714 and width 716may vary widely based on numerous possible configurations of gantry 700.In some embodiments either or both of height 714 and width 716 may be aslittle as 2.5 meters.

In some embodiments, gantry 700 may be separated from other componentsof system 300 by a wall 702, or other barrier. Wall 702 may include oneor more openings (not shown in figures) to allow passage of proton beam318 and any beam line or other equipment configured to deliver protonbeam 318. Location of wall 702 may vary, depending on a number offactors and in some embodiments wall 702 may not be present.

Solenoid 704 may be configured to capture protons emitted byion-generating target 304. In some embodiments, protons emitted byion-generating target 304 may exhibit a large divergence. As an example,beam size of protons emitted from ion-generating target 304 may expandby a factor of 100 over a short distance, such as 1 cm. Solenoid 704 maybe configured to reduce convergence of proton beam 318.

Solenoid 704 may include a high-field solenoid, such as, for example, asuperconducting solenoid at 9 to 15 T. Field strength may be related tosolenoid length and resulting beam size. Higher solenoid field strengthmay result in smaller beam size and aperture required in solenoid 704.Solenoid 704 may vary in length based on field strength and otherfactors. In some embodiments, solenoid 704 may be between 0.55 m and0.85 m in length with an aperture between 4 cm and 20 cm. In someembodiments, solenoid 704 may be used in conjunction with one or morecollimators. Further, in some embodiments, one or more quadrupoles maybe employed in addition to or as an alternative to solenoid 704.

Coupling 706 may be any mechanical and or optical connection configuredto facilitate physical movement of gantry 700, such as rotation about anaxis of rotation, such as axis 716. Gantry may be configured to bephysically moved by any appropriate arrangement of motors and/oractuators, which may be controlled by control system 314. Coupling 706may include one or more bearings or bushings and may be connected toand/or integrated into a beam line carrying proton beam 318. Therefore,coupling 706 may be configured to maintain a seal or other barrier toprevent loss of a vacuum state or other environmental conditions withinthe beam line. Further, coupling 706 may include rotationally invariantoptics, for example to reduce tune dependence as a function of gantryposition.

Gantry 700 may further include beam adjustment component(s) 708. Beamadjustment components 708 may include any of beam adjustment components308 discussed above, configured to guide proton beam 318 through thegantry. In some embodiments, beam adjustment components 708 may includeelectromagnets, such as dipoles and/or quadrupoles, configured to divertproton beam 318 through gantry 700. Beam adjustment components 708 mayinclude normal conducting dipoles, superferric superconducting dipoles,stripline dipoles, etc.

In some embodiments, beam adjustment components 708 may include dipolepairs (e.g., each bending proton beam 318 by approximately 45°) to forma rectangle (or any other combinations of angles to form a rectangle oranother desired shape). The dipole pairs may operate at about 4.8 T andbe about 0.6 m long. Straight sections between dipole pairs may beadjusted independently, providing tuning range, flexibility andtherefore customization in the electromagnetic optics. Splitting 90°bends into two may improve reference trajectory control, as each dipolemay be adjusted independently, for example via shunts on a single powersupply, providing at least 10% variation (20% total relative changeconsidering two). Thus, dipole pairs may facilitate independenttrajectory correction on each arm of gantry 700, decreasing tolerancesand cost.

Gantry 700 may also include one or more collimators 718. Collimators 718may be configured to filter proton beam 318 such that only protonstraveling in a desired direction and/or having a desired momentum areallowed to pass. Collimators 718 may be disposed in a variety oflocations within gantry 700. For example, if beam adjustment components708 have achromatic properties producing undesired effects on the beamdownstream, collimators 718 may be configured to counteract sucheffects.

Gantry 700 may further include scanning magnet(s) 710. Scanning magnets710 may include beam adjustment components, such as beam adjustmentcomponents 308 or 708, configured to adjust isocenter 712's location inspace. Scanning magnets 710 may be controlled by control system 314, forexample to adjust location of treatment being provided to a treatmentvolume. Scanning magnets 710 may be disposed in any of a number oflocations within gantry 700. For example, scanning magnets 710 may beupstream from one or more of beam adjustment components 708, downstreamof all of beam adjustment components, or a combination of such upstreamand downstream locations, as shown in FIG. 7.

System 300 may be configured such that scanning magnets are operated incooperation with other components in order to control the location oftreatment within a patient. For example, control system 314 may controlany combination of scanning magnets 710, movement of gantry 700, andmovement of patient support platform 312. One or more components may beconfigured for control of particular dimensions and/or degrees offreedom. For example, patient support platform may be configured toadjust patient position in one dimension, while scanning magnets 710adjust in another dimension, orthogonal to the first.

Alternatively or additionally, system 300 may be configured such that acoarse adjustment in a given dimension may be performed by a differentcomponent than a fine adjustment. For example, a coarse adjustment in aparticular dimension may be performed by a motor configured tomanipulate patient support platform 312, while fine adjustment may beperformed by a scanning magnet 710. Numerous combinations of suchadjustments will be apparent to those of skill in the art.

FIG. 8 depicts a further example of a gantry 800. Gantry 800 may includesome or all of the same components as gantry 700, such as solenoid 704,coupling 706, beam adjustment component(s) 708, collimator(s) 718, andscanning magnet(s) 710, and may further include additional quadrupoleelements 802. Quadrupole elements 802 are magnetic elements that arepart of the magnetic beam line and help deliver the proton beam to thetreatment volume. Quadrupole elements 802 are typically used to focus orde-focus a beam of charged particles, as opposed to some larger dipolesthat may often be used as bending magnets to bend the proton beam.Quadrupole elements 802 may be permanent magnets (e.g., made ofrear-earth elements and/or other magnetic materials), normal-conductingelectromagnets, super-conducting electromagnets, pulsed magnets, orother devices capable of providing the appropriate fixed or tunablemagnetic field.

FIG. 9 is an exemplary flow chart of a process 900 for proton beamformation. In step 902, an electromagnetic radiation source (e.g.,source 302) may emit an electromagnetic radiation beam (e.g., beam 316).In step 904, the electromagnetic radiation beam may strikeion-generating target (e.g., target 304). In step 906, interaction ofthe electromagnetic radiation beam with the ion-generating target maygenerate particles, including protons. In step 908, proton beamadjustment component(s) (e.g., components 308) may form a proton beam(e.g., beam 318) from the particles and direct the proton beam to thetreatment volume in the patient. The steps of process 900 may be carriedout automatically, such as by control system 314. The steps of process900 may also be carried out in response to user input, such as throughcontrol system 314 or carried out by a combination of automatic andmanual operation of various components. In some embodiments, process 900may be carried out based on specifications in a treatment plan, whichmay be customized to varying degrees based on a particular patient,treatment type, and/or treatment volume.

The electromagnetic radiation beam emitted in step 902 may be generatedvia any components capable of radiation beam generation, such as, forexample, various combinations of the components described in relation toFIG. 6.

In step 904, the electromagnetic radiation beam may strike andion-generating target. For example, ion-generating target 304 may bedisposed within an interaction chamber, isolating the ion-generatingtarget from the outside environment. Upon striking ion-generating target304, an interaction of electromagnetic radiation beam 316 andion-generating target 304 may generate various particles, includingprotons that may be used in proton beam 318. In some embodiments,protons may be emitted at a proton energy of about 250 MeV from alocation on ion-generating target 304 struck by electromagneticradiation beam 316 focused to a spot size of about 10 to 100 μm. Thetwo-dimensional divergence angle of protons emitted from ion-generatingtarget 304 may be about 0.2 radians (i.e., about 11 degrees). Inaddition, proton energy angular distribution ∂Ω/∂E and proton numberenergy distribution ∂N/∂E may be very small so that the energy angulardistribution and proton number energy distribution are reasonablyconstant. As an example, a pulse of electromagnetic radiation beam mayresult in the emission of 10⁸ protons, and pulses may be repeated at arate of 10 to 1000 Hz. Accordingly, a pulsed electromagnetic radiationbeam 316 may thereby produce a pulsed proton beam 318. A pulse ofprotons may also be referred to as a proton “bunch.”

In accordance with the present disclosure, an ion-generating target maybe supported by and/or housed within an interaction chamber. As used inthe present disclosure, an interaction chamber may refer to anystructure configured to isolate the target from ambient conditions andto provide an appropriate environment for ion generation.

In accordance with the present disclosure, the interaction chamber may,for example, comprise a target stage. As used in the present disclosure,a target stage may refer to any structure configured to support anion-generating target. In some embodiments, a target stage may becontrolled by a processor configured to cause relative movement betweenthe target stage and an electromagnetic radiation beam.

In accordance with the present disclosure, the interaction chamber maycomprise one or more detectors. As used herein, a detector may refer toa device that detects one or more properties of a sample chambercondition, an electromagnetic radiation source or beam, a proton beam,and/or a laser-target interaction. A detector may, for example, observeany condition within and/or proximate to the interaction chamber. Insome embodiments, a system for generating a proton beam may includeother detectors separate from an interaction chamber. As an example, adetector may be configured to measure at least one laser-targetinteraction property.

As used in the present disclosure, a laser-target interaction may referto an observable property related to the interaction of anelectromagnetic radiation beam with an ion-generating target.Laser-target interaction properties may include, for example, a protonbeam property, a secondary electron emission property, an x-ray emissionproperty, a proton beam energy, a proton beam flux, and/or otherproperty indicative of the interaction between an electromagneticradiation beam and an ion-generating target.

FIG. 10 depicts an example of an interaction chamber 1000. Interactionchamber 1000 may be any size and shape, and may be constructed of anyappropriate material or materials capable of housing a target duringlaser-target interaction. Stainless steel is one example of a materialthat may be used to construct the interaction chamber 1000.

Interaction chamber 1000 may include one or more stages 1002 configuredto support ion-generating target 304 and/or other equipment withininteraction chamber 1000, such as optics component(s), beam adjustmentcomponent(s), detectors, or the like. Stage(s) 1002 may be fixed oradjustable. An adjustable stage may be configured for translation and/orrotation along one or more axes. Adjustment of stage(s) 1002 may bemanual or automated. Automated adjustment may be performed, for example,in response to one or more signals provided by control system 314.Stage(s) 1002 may optionally be configured to heat, cool, or maintainthe temperature of ion-generating target 304. Temperature control may beachieved, for example, by monitoring the temperature of ion-generatingtarget 304 and raising, lowering, or maintaining the temperature ofion-generating target 304 in response to the measured temperature.Temperature monitoring can be achieved, for example, with one or morethermocouples, one or more infrared temperature sensors, and/or anyother technique used to measure temperature. Temperature adjustment maybe made, for example, by adjusting the amount of electric currentflowing through a heating element. The heating element may be, forexample, a refractory metal such as tungsten, rhenium, tantalum,molybdenum niobium, and/or alloys thereof. Temperature adjustment mayalso be made, for example, by flowing a coolant, such as water or acryogenic fluid (e.g., liquid oxygen, liquid helium, liquid nitrogen,etc.) through a conduit directly or indirectly placed in thermalcommunication with ion-generating target 304. As a person of ordinaryskill in the art would appreciate, these exemplary manners of adjustingtemperature are compatible and may be combined. Of course, thesetemperature adjustment methods are not limiting, and any other knownmethod for heating, cooling, and or maintaining the temperature ofion-generating target 304 may be used with the disclosures herein.

Interaction chamber 1000 may include one or more associated vacuumpump(s) 1004. For example, either or both of sample preparation andproton beam formation may have sub-atmospheric atmospheric pressurerequirements or may achieve optimal performance within a particularrange of sub-atmospheric pressures. Vacuum pump(s) 1004 may be used toinfluence pressure conditions within interaction chamber 1000 and/orcomponents associated with interaction chamber 1000. For example, vacuumpump(s) 1004 may maintain a vacuum condition or near-vacuum condition ininteraction chamber 1000. Examples of vacuum pump(s) 1004 may includeone or more turbo-molecular pumps, cryogenic pumps, ion pumps, ormechanical pumps, such as diaphragm or roots pumps. Vacuum pump(s) 1004may operate in conjunction with one or more pressure regulators (notshown in figures).

Interaction chamber 1000 may include optics components 1006. Any of thecomponents noted above with respect to optics component(s) 306 may beused inside the interaction chamber to further direct electromagneticradiation beam 316. For example, as shown in FIG. 10, interactionchamber may include mirrors 1006 a configured to direct electromagneticradiation beam 316 toward ion-generating target 304. In an embodiment,interaction chamber 1000 may include a parabolic mirror 1006 bconfigured to focus electromagnetic radiation beam 316 ontoion-generating target 304.

Interaction chamber 800 may include any number of proton beam adjustmentcomponent(s) 308. For example, as shown in FIG. 8, interaction chamber1000 may include a collimator 1010. Those of skill in the art willappreciate that alternatively or additionally, other proton beamadjustment component(s) 308 may be included in interaction chamber 800.In various embodiments, any of the beam adjustment component(s) 308 maybe incorporated into interaction chamber 1000.

Interaction chamber 1000 may include or interface with a beam line 1012,as described above in association with proton beam adjustmentcomponent(s) 308. Beam line 1012 may include a conduit maintained atsub-atmospheric pressures to facilitate propagation of proton beam 318.Beam line 812 may include proton beam adjustment components, such as anyof the elements referenced above with respect to proton beam adjustmentcomponent(s) 308. Beam line 812 may also include vacuum pumps, such asany of the pumps described in relation to vacuum pump(s) 1004, toachieve and/or maintain sub-atmospheric conditions.

Interaction chamber 1000 may include one or more valve(s) 1014. Anysuitable valve(s) may be used, and may be located, for example, betweenvarious portions of interaction chamber 1000 or between interactionchamber 1000 and other components of system 300 or its ambientenvironment. Valve(s) 1014 may be configured, for example, to isolatevacuum pump(s) 1004 or beam line 1012. Valve(s) 1014 may be manual orautomatic. Automatic valves may be, for example, pneumatic and/orelectronic. Valve(s) 1014 may be simple open/close valves, such as atwo-position gate valve, or valve(s) 1014 may be configured to bepartially open. Valve(s) 1014 associated with vacuum pump(s) 1004 may,for example, include one or more butterfly valve(s) that can varycontinuously between open and closed states. Valve(s) 1014 may beconfigured to maintain pressure, retain or release materials, and/orallow access to interaction chamber 800 for maintenance of parts orreplacement of ion-generating targets.

Interaction chamber 1000 may include one or more shutter(s) 1016.Shutter(s) 1016 may be configured, for example, to block or allowelectromagnetic radiation beam 1016 into chamber 1000. Shutter(s) 1016may be, for example, a simple open/close shutter. Shutter(s) 1016 mayalso be configured to chop electromagnetic radiation beam 316 ifdesired. Operation of shutter(s) 1016 may be manual or automated.Automated operation may occur, for example, in response to one or moresignals provided by control system 314.

Interaction chamber 1000 may include one or more windows 1018. Windows1018 may be composed of any material suitable for the pressure,temperature, and other environmental factors associated with interactionchamber 1000.

As described above, interaction chamber 1000 may be configured forforming an ion-generating target in situ. System 300 may also include aseparate or substantially separate preparation chamber (not shown inFIG. 6 or 10) connected to interaction chamber 1000 and configured fortarget preparation and/or conditioning. The preparation chamber mayinclude various equipment and instrumentation for preparingion-generating targets, such as equipment that may be found in systemsfor performing evaporation, physical vapor deposition, chemical vapordeposition, molecular beam epitaxy, atomic layer deposition, and thelike. The preparation chamber may also include one or more stage(s) forholding ion-generating target 304 or a target substrate that will serveas a template to form ion-generating target 304. The preparation chambermay also include mechanisms for transferring the ion-generating targetinto place in the interaction chamber following preparation.Alternatively or in addition to using a separate or substantiallyseparate preparation chamber, interaction chamber 1000 may be similarlyequipped so that sample preparation or conditioning may take placewithin interaction chamber 1000 (not shown in FIG. 6 or 10).

The preparation chamber may also include temperature control elements(as described above with respect to stages 1002), one or more sampletransfer mechanisms, such as a transfer arm or any other transfer devicewell known by those familiar with vacuum systems. System 300 may alsoinclude a load lock between sample preparation chamber and interactionchamber 1000.

Interaction chamber 1000 may further include heating and or coolingelements (not shown in FIG. 10). Either or both of sample preparationand particle beam formation may have temperature requirements or mayachieve optimal performance within a particular range of temperatures.Interaction chamber may include heating elements and/or cooling elementsconfigured to achieve and maintain such temperature conditions. Theheating and cooling elements may comprise any of the temperature controlequipment and/or methods described in relation to stage(s) 1002 butconfigured to control temperature conditions of other portions ofinteraction chamber 1000 or of interaction chamber 1000 at large.

Interaction chamber 1000 may include one or more detectors 1020.Detectors 1020 may be configured to measure conditions associated withinteraction chamber 1000. In some embodiments, measurements may be takenon a single-shot basis. That is, detectors 1020 may be configured tomeasure properties associated with an individual interaction betweenelectromagnetic radiation beam 316 and ion-generating target 304.Detectors 1020 may also measure the same or different properties on amore continuous basis, for example, providing results after processing.

Placement of detectors 1020 may vary based on a number of factors,including space constraints and optimal location for measurement. Asshown in FIG. 10, detectors 1020 may be located along an outer wall ofinteraction chamber 1000 (such as detector 1020 a), proximate toion-generating target 304 (such as detectors 1020 b and 1020 c), or inline with proton beam 318 (such as 1020 d).

For some detectors 1020, there may be an advantage to detectionproximate to ion-generating target 304, and thus to interaction betweenelectromagnetic radiation beam 316 and ion-generating target 304(laser-target interaction). In an embodiment, system 300 may bestabilized over time, after which such proximity may be unnecessary. Insome embodiments, one or more detectors 1020 may be mounted outside ofinteraction chamber 1000. For example, FIG. 10 depicts detector 1020 eoutside interaction chamber 1000 proximate to window 1018. Detectors1020 may be disposed such that they are inherently subject to propertiesintended to be measured or conditions within interaction chamber 1000may be altered to facilitate measurement. For example, opticscomponent(s) 1006 may include a steering mirror configured totemporarily or intermittently deflect a signal from an interaction areato a detector, such as detector 1020 e through window 1018. The abovedetector placements are merely exemplary, and numerous others may beapparent to those of skill in the art.

In some embodiments, one or more detectors 1020 may be configured tomeasure one or more laser-target interaction properties ofelectromagnetic radiation beam 316 or proton beam 318. In someembodiments, detectors 1020 may include quadrupole analyzers, sphericalmirror analyzers (“SMAs”), cylindrical mirror analyzers (“CMAs”),secondary electron detectors, photomultipliers, scintillators,solid-state detectors, time-of-flight detectors, laser-on-target opticaldiagnostic detectors, x-ray detectors, cameras, Faraday cups, or otherdetectors. Detectors 1020 may detect properties such as absorption orreflection, a secondary electron emission property, a plasma propertysuch as electron temperature and/or density, and/or an x-ray emissionproperty. Secondary emissions, such as emission of electrons and/orx-rays may be indicative of laser-target interaction properties and/orproperties of proton beam 318. For example the energy spectrum and/orflux of electrons and/or x-rays may indicate proton beam properties.These signals may then be used as input in a feedback loop for modifyingthe laser-target interaction, for example, by adjusting one or more ofelectromagnetic radiation source 302, optics component(s) 306, protonbeam adjustment component(s) 308, and the position/orientation ofion-generating target 304, as described in greater detail below.

Detectors 1020 may be configured to detect proton beam direction,spatial spread, intensity, flux, energy, proton energy, and/or energyspread. For example, in some embodiments, a Thompson parabola may beemployed. In such embodiments, proton beam 318 may be directed into anarea in which magnetic and electric fields deflect the protons tolocations on a detection screen. The location at which the protonscontact the screen may indicate proton energy. For such a screen, anyproton sensitive device may be used, such as CR-39 plates, image plates,and/or scintillators (coupled to a imaging device such as a CCD camera).As another example spatial proton beam distribution may be detected witha screen sensitive to protons, such as CR-39 and image plate or ascintillator with a detection device (such as a camera) may be used.

Detectors 1020 may also include a time-of-flight detector. The time offlight detector may measure average proton energy. In some embodiments,the time of flight detector may include a proton scintillator and adetector with adequate temporal resolution, such as aphoto-multiplier-tube (PMT). The time when the proton signature isdetected on the PMT may indicate proton velocity and thus proton energy.

Detectors 1020 may also include instruments configured for plasmadiagnostics, such as x-ray spectrometers configured to detect electrontemperature and density, or interferometers configured to detect plasmadensity. Optical diagnostics may include imaging of the reflected laserbeam to measure the laser absorption efficiency. These detectors may beused during initial system design, calibration, and testing, and theymay optionally be included in the final system.

Referring back to FIG. 9, in step 906 interaction of an electromagneticradiation beam (e.g., 316) with ion-generating target (e.g., 304) maygenerate particles, including protons. In some embodiments, the surfaceof ion-generating target 304 may be scanned by electromagnetic radiationbeam 316. For example, the electromagnetic beam 316 may be sequentiallyscanned over the surface of ion-generating target 304 by continuous ordiscontinuous rastering, stepwise scanning, or any other scanningwaveform desired. Alternatively, the electromagnetic beam 316 may benon-sequentially scanned over the surface of ion-generating target 304.Electromagnetic radiation beam scanning may be achieved by manually orautomatically adjusting one or more optics component(s) 306 locatedbetween electromagnetic radiation source 302 and ion-generating target304. Automatic adjustment of optics component(s) 306 may be achieved,for example, in response to one or more signals provided by controlsystem 314. The one or more control signals provided by control system314 may be predetermined by a program, such as a program stored incomputing system 500, or they may be provided in response to one or morefeedback signals received from various elements of system 300, such asone or more detectors. For example, information from the one or moredetectors in system 300 may indicate that altering the location of thelaser-target interaction site is desirable. This and other examples offeedback are discussed in greater detail below.

In step 908, system 300 may form proton beam 318 from the particles anddirect proton beam 318 to the treatment volume. Protons generated instep 906 may not initially be disposed in a useful configuration ortrajectory. The protons may be formed into a proton beam, for example byone or more beam adjustment component(s) 308. Properties of the protonbeam may vary based on the configuration of system 300 and from use touse. In an embodiment, the proton energies may be about 250 MeV, asnoted above, and may range, for example, from 60 to 250 MeV. Proton fluxmay be about 2 Gy/min, and proton pulse duration may be less than 100psec. Protons generated by system 300 may also have a symmetric phasespace profile, allowing improvements in proton beam steering andfiltering over accelerator-based proton generation systems, therebyimproving the accuracy and the efficiency of proton beam delivery andtreatments. Of course, the above ranges are only examples, and thespecific energies and flux may vary based on particulars of theconfiguration.

In accordance with the present disclosure, feedback may be used toadjust one or more properties of a proton beam. As used in the presentdisclosure, feedback may refer to a control protocol in which one ormore system output is routed back into the system (i.e., fed back intothe system) as one or more input as part of a cause-and-effect chain.For example, a processor (as described above) may be configured toproduce a feedback signal to control aspects of an electromagneticradiation beam, a proton beam, and/or a laser-target interaction. Such afeedback signal may, for example, be based on one or more property of anelectromagnetic radiation beam, a proton beam, and/or a laser-targetinteraction. In some embodiments, a feedback signal may alter a protonbeam by adjusting at least one of an electromagnetic radiation source,one or more optics components, and/or a position or orientation of anelectromagnetic radiation beam relative to an ion-generating target.Feedback may, in some instances, be used to determine a structure of anion-generating target.

Feedback signals may be configured to alter aspects of anelectromagnetic radiation beam. For example, a processor may generateone or more feedback signal configured to adjust an electromagneticradiation source to alter a temporal profile of an electromagneticradiation beam. Further, an electromagnetic radiation source may beconfigured to generate a main pulse and a pre-pulse of anelectromagnetic radiation beam, and a processor may configured to causethe electromagnetic radiation source to alter a contrast ratio of thepre-pulse to the main pulse in response to a feedback signal.

Moreover, a processor may be configured to generate a feedback signal toalter an energy of an electromagnetic radiation beam or a spatial ortemporal profile of an electromagnetic radiation beam. For example, oneor more optics component(s) may alter a spot size of an electromagneticradiation beam in response to a feedback signal. In some embodiments, amotor may alter a relative orientation between an electromagneticradiation beam and an ion-generating target in response to a feedbacksignal. And in some embodiments, an adaptive mirror may direct anelectromagnetic radiation beam at an ion-generating target in responseto a feedback signal.

In some embodiments, feedback may be used to adjust properties of protonbeam 318. FIG. 11 depicts a process flow in an exemplary process 1100for employing such feedback. At step 1102, system 300 may determine orbe programmed with a desired value of a laser-target interactionproperty. The laser-target interaction property may be based on any ofthe properties detected by any of detectors 1020 described above. Thedesired value may be based, for example, on a nominal value related to aquality desired in proton beam 318, a value based on a desired propertyin a treatment plan, an optimal operating state of system 300, etc.

At step 1104, system 300 may generate one or more feedback signal(s)based on the detected laser-target interaction property. Feedback may bereceived and/or processed by control system 314. For example, controlsystem 314 may calculate adjustments to various components of system 300by comparing a laser-target interaction property to the desired value ofthe laser-target interaction property established at step 1102. In someembodiments, adjustment and comparison may be carried out according to afeedback control algorithm, such as a PID(proportioning-integrating-differentiating) control loop. Therelationship(s) defined by the feedback signal(s) may be linear (e.g.,an increase of pulse duration may affect proton energy inversely(E_(p)˜1/t)). The feedback signal may, at times (e.g., during startup oridle periods), be set to zero, set to an initial value indicating noadjustment is necessary, or set to a default value indicating an initialstate.

At step 1106, system 300 may adjust one or more system components basedon the feedback signal. For example, in some embodiments control system314 may be configured to adjust a property of electromagnetic radiationbeam 316 based on the feedback signal. The generated feedback may causea motor to adjust a path of electromagnetic radiation beam 316. Themotor may, for example adjust one or more of optics component(s) 306.Such adjustments may, for example, cause electromagnetic radiation beam316 to strike ion-generating target 304 at a more desirable location orlocations, thereby altering a property of proton beam 318 resulting fromelectromagnetic radiation beam 316 striking ion-generating target 304.Such adjustments may also cause electromagnetic radiation beam tosequentially strike a plurality of contiguous features of ion-generatingtarget 304, such that the features are irradiated at a desired rate.Additionally, optics component(s) 306 may be configured to scanelectromagnetic radiation beam 316 over a surface of ion-generatingtarget 304. As another example, ion-generating target 304 may bemanipulated by a motor based on the feedback signal to moveion-generating target 304 in any of six degrees of freedom.

In some embodiments, at step 1108, control system 314 may causeelectromagnetic radiation source 302 to alter an energy, wavelength, ortemporal or spatial profile of electromagnetic radiation beam 316 inresponse to the feedback signal. Control system 314 may also causeelectromagnetic radiation source 302 to alter a contrast ratio of apre-pulse to a main pulse in response to the feedback signal. Suchadjustments to electromagnetic radiation beam 316 via electromagneticradiation source 302 may be achieved, for example, by adjusting one ormore of the oscillator(s) 602, pump source(s) 604, optics 606,stretcher(s) 610, amplifier(s) 612, and compressor(s) 614 viacontroller(s) 616. In some embodiments, any optical element or othercomponent of electromagnetic radiation source 302 or optics component(s)306 may be changed, moved, oriented, or otherwise configured based onthe feedback signal, resulting in any number of changes. The examplesabove are not intended to be limiting.

At step 1108, system 300 may direct electromagnetic radiation beam 316to strike ion-generating target 304, for example as described above inrelation to steps 902 and 904 of process 900, shown in FIG. 9.

At step 1110, system 300 may detect a laser-target interaction property.The detected laser-target interaction property may include any one ormore of the properties described above in relation to detectors 1020and/or any property detected in relation to electromagnetic radiationbeam 316, proton beam 318, the laser-target interaction, faultconditions, or any other signal generated by any component of thesystem.

The laser-target interaction property detected at step 1110 may bepassed back to step 1104, and process 1100 may repeat any number oftimes. For example, process 1100 may repeat a standard, fixed number oftimes, a number of times preset by control system 314, a number of timesdefined by a treatment plan, or a variable number of times determined inreal-time.

In some embodiments, selection of protons of a particular energy and/orflux may be desired. For example, as described above with respect to theadvantages of proton therapy, treatment of a treatment volume of aparticular depth within a patient may be desired. Treatment depth may bespecified by selectively emitting protons of a particular energy levelor range of energy levels. The dose of radiation delivered to thetreatment volume depends in part of the flux of the proton beam.Accordingly, it may be desirable to adjust the proton flux and protonenergy produced by system 300.

In accordance with the present disclosure, a system for directing apulsed beam of charged particles may include an ion source. As used inthe present disclosure, an ion source may refer to any structure ordevice configured to produce a continuous or pulsed ion beam. A pulsedion beam may refer to any group of ions that includes at least one ionbunch (e.g., a cluster of ions). In some embodiments, an ion source mayinclude at least a radiation beam and an ion-generating target asdescribed above; however, this example is not limiting. For example, asystem for directing a pulsed beam of charged particles consistent withthe present disclosures may be used with any beam of charged particlesgenerated by any method or device (including, for example, a cyclotron,synchrotron, or other particle accelerator).

Further, in accordance with the present disclosure, a system fordirecting a pulsed beam of charged particles may include at least oneelectromagnet. As used herein, an electromagnet may refer to any devicecontrollable to generate an electromagnetic field. In some embodiments,the at least one electromagnet may include a plurality of electromagnetsin series along a trajectory of a pulsed ion beam.

Further, consistent with the present disclosure, a system for directinga pulsed beam of charged particles may include at least a zone proximatean electromagnet. As used in the present disclosure, a zone proximate toan electromagnet may refer to any location in which an electromagneticfield generated by the electromagnet is capable of altering thetrajectory of a charged particle located within the zone. For example, azone proximate to an electromagnet may include any location orientedsuch that an ion beam may traverse therethrough. In some embodiments,the zone may include a location within an electromagnetic field createdby activation of an electromagnet. The size of the zone may varydepending on a number of factors; however, in some embodiments, the zonemay have a dimension smaller than about one inch.

In accordance with the present disclosure, a system for directing apulsed beam of charged particles may include at least one automatedswitch. As used in the present disclosure, an automated switch may referto a device configured to be electrically connected to an electromagnetand configured to selectively activate or deactivate the at least oneelectromagnet when triggered by a signal. An automated switch may be anyswitch that may be selectively activated or deactivated. For example,the automated switch may include a photoconductive semiconductor switchor a spark switch. In some embodiments, the at least one automatedswitch may include a plurality of automated switches. Individualautomated switches may be associated with different electromagnets orwith the same electromagnet. In some embodiments, a first electromagnetmay be configured to divert a portion of a pulsed ion beam from anoriginal trajectory to a diverted trajectory. Some embodiments mayfurther include a second electromagnet in series with the firstelectromagnet and configured to re-divert at least part of the divertedportion of the pulsed ion beam from the diverted trajectory to a pathsubstantially parallel to the original trajectory.

In accordance with the present disclosure, a system for directing apulsed beam of charged particles may include a radiation trigger source.As used in the present disclosure, a radiation trigger source mayinclude any structure capable of producing radiation trigger to activateor deactivate at least one automated switch. For example a radiationtrigger source may include one or more of an ion source, an x-raysource, an electron source, and a light source (e.g., a laser). In someembodiments, a radiation trigger produced by a radiation trigger sourcemay be configured to activate or deactivate an automated switch and toirradiate an ion-generating target to thereby generate the pulsed ionbeam.

In accordance with the present disclosure, at least one processor may beconfigured to activate least one electromagnet as an ion bunch traversesa zone proximate to the electromagnet. The at least one processor mayinclude any of the processors described above and may be configured toactivate a plurality of automated switches in sequence as the ion bunchtraverses a series of electromagnets.

In accordance with the present disclosure, a controlled delay line maybe provided. As used in the present disclosure, a controlled delay linemay refer to a pathway configured to extend the time it takes for a beamof radiation or charged particles to traverse it. For example, acontrolled delay line may be used to delay the time at which an ionbunch traverses a zone proximate to an electromagnet. As anotherexample, a controlled delay line may be used to delay the time at whicha radiation beam activates an automated switch. In some embodiments thecontrolled delay line may be configured to synchronize the time at whichthe radiation beam activates an automated switch of an electromagnetwith the time at which a pulsed ion beam traverses a zone proximate tothe electromagnet.

FIG. 12 is an exemplary graph of a proton energy profile for an ionbunch, for example a proton bunch within proton beam 318. Pulse (i.e.,“bunch”) 1202, shown in FIG. 12, may be generated as described above inrelation to system 300 and ion-generating target 304. Use ofion-generating target 304, however, is merely an example, and is notintended to be limiting. Other ion sources and type of ions may also beused.

In the context of proton therapy, to irradiate a treatment volumelocated at a particular depth within a patient, protons of certainenergies may be desired. To isolate protons of the desired energies,system 300 may filter proton beam 318 to deliver protons having thedesired energies to the patient, eliminating protons having otherenergies from the proton beam. For example, to deliver protons 1204having energies between energy 1206 and energy 1208, system 300 mayfilter proton bunch 1202 by removing any protons having energies lessthan energy 1206 and greater than energy 1208.

Such filtering may be achieved by combining certain proton beamadjustment components 308. For example, proton beam adjustmentcomponents 308 may manipulate proton beam 318 such that protons havingcertain energies are diverted along a different trajectory than protonshaving other energies. This may be achieved in a number of ways. Forexample, proton beam adjustment components 308 may be configured as aband pass filter to isolate protons having energies between energy 1206and energy 1208. In another embodiment, proton beam adjustmentcomponents 308 may be configured as a high pass filter to isolateprotons having energies greater than an energy cut-off, such as energy1206 or 1208. In another embodiment, proton beam adjustment components308 may be configured as a low pass filter to isolate protons havingenergies less than an energy cut-off, such as energy 1206 or 1208.

The above embodiments may be combined, and more than one filter may beused. A low pass filter and a high pass filter may be combined inseries, for example, to create a band pass filter. In such anembodiment, the low pass filter may be configured to isolate protonshaving energies less than energy 1208, and the high pass filter may beconfigured to isolate protons having energies greater than energy 1206.This may be particularly advantageous for selecting protons within anarrow energy band, especially an energy band narrower than astand-alone band pass filter can accommodate.

To achieve proton energy filtering, one or more of proton beamadjustment components 308 may be selectively activated and/or controlledby one or more automated switches, such as a spark switch orphotoconductive switch. Selective activation may be governed bycontroller 314, which may have interfaces with the automated switch andthe proton beam adjustment components 308. The automated switch may beactivated or deactivated by a signal generated by controller 314. Thesignal may be generated based on feedback, such as any of the forms offeedback described above.

Additionally or alternatively, in some embodiments the automated switchmay be configured for activation or deactivation by electromagneticradiation, such as a laser or another light source. For example, theautomated switch may comprise a photoconductive semiconductor switchdisposed along a path of electromagnetic radiation beam 316.Alternatively, electromagnetic radiation beam 316 may be diverted by oneor more of optics components 306 or split into a plurality of beams byoptics components 306, one or more of the plurality of beams beingdelivered to the automated switch. In such embodiments, the automatedswitch may be activated or deactivated when struck by electromagneticradiation beam 316. Thus, electromagnetic radiation beam may beconfigured both to activate the automated switch and to irradiateion-generating target 304 to generate the proton beam 318.

In other embodiments, a switching electromagnetic radiation source maynot be associated with electromagnetic radiation source 302 orelectromagnetic radiation beam 316. For example, control system 314 maycause a separate switching electromagnetic radiation source to irradiateone or more photoconductive semiconductor switch or spark switch,thereby activating or deactivating the proton beam adjustment components308 of the proton energy filter(s).

Timing associated with activating the automated switch in a protonenergy filter may be influenced, at least in part, by a time-of-flightcontrol unit, such as a controlled delay line configured to adjust atime at which the radiation beam activates the automated switch. Forexample the controlled delay line may be configured to synchronizetiming of the automated switch with the radiation beam. Additionally, orin the alternative, the timing associated with activating the automatedswitch in a proton energy filter may be controlled by control system314, for example in response to a user command, a feedback signal fromsystem 300, or in accordance with a predetermined program.

Although the above discussion contemplates an application in whichprotons are filtered in a proton therapy system, a person of ordinaryskill in the art would appreciate that these filtering systems andmethods have broad applicability. For example, these methods and systemsdescribed in the context of filtering protons may also be used to filterany variety of other charged particles used in any variety of othersystems and applications.

FIG. 13 depicts an example of a configuration of proton beam adjustmentcomponents 308 configured to achieve proton energy selection asdescribed above. Such a configuration may include one or more protonbeam adjustment components 1302 and 1306, and a beam dump 1304.

In some embodiments, beam adjustment components 1302 and 1306 mayinclude a plurality of electromagnets disposed in series along atrajectory of proton beam 318. A plurality of automated switches may beassociated with one or more different magnets or groups of magnets.Control system 314 may be configured to activate such a plurality aswitches in various combinations to manipulate proton beam 318. Forexample, control system 314 may activate the automated switches insequence as a proton bunch traverses magnets of the plurality ofelectromagnets. In an embodiment, beam adjustment component 1302 may beconfigured to divert a portion of proton beam 318 from an originaltrajectory to a diverted trajectory. Beam adjustment component 1302 maybe configured to redivert at least part of the diverted portion of thepulsed proton beam from the diverted trajectory to a path substantiallyparallel to the original trajectory.

As shown in FIG. 13, proton beam 318 may pass through a zone proximateto proton beam adjustment component 1302. The zone may be of any size,but in some embodiments may have a dimension of less than one inch. Thezone proximate to proton beam adjustment component 1302 may beconfigured and/or oriented for a proton beam 318 (e.g., a continuousbeam or a pulsed beam including pulses such as pulse 1202) to traversethe zone. Proton beam adjustment component 1302 may include any ofproton beam adjustment components 308, for example, an electromagnetsuch as a dipole, CMA, SMA, or time-of flight analyzer. As the protonbeam traverses the zone proximate to proton beam adjustment component1302, the automated switch may activate proton beam adjustment component1302 such that protons having the desired energy are diverted along atrajectory 1310 toward beam adjustment component 1306, as shown in FIG.13A. As protons having energies to be filtered out of proton beam 318traverse the zone proximate to proton beam adjustment component 1302,the automated switch may not be activated, or an alternative switch maybe activated, and the protons may travel along trajectory 1308 towardbeam dump 1304, as shown in FIG. 13B. Protons having the desired energymay pass beam adjustment component 1306, where they are redirected backalong a beam line trajectory 1312 and eventually toward the treatmentvolume.

In some embodiments (not shown), a proton energy filter may include onlya single beam adjustment component and a beam dump. Instead of divertingprotons having the desired energy towards a second electromagneticelement, protons having the desired energy may be allowed to passthrough the zone proximate to proton beam adjustment component withoutbeing diverted. As protons having energies to be filtered out of theproton beam pass through the zone proximate to proton beam adjustmentcomponent, they may be diverted along a trajectory towards the beamdump.

In some embodiments, a proton energy filter may include an energydegrader. For example, an energy degrader may be used as part of beamdump 1304. Additionally, an energy degrader may be used to reduce energyand/or flux of the protons that are not diverted to the beam dump. Tofilter proton beam using an energy degrader, protons may be divertedthrough the degrader, where they interact with the degrader. Protonstransmitted through the degrader along the trajectory of the proton beamthen have reduced energies, thereby lowering the energy of the protonbeam. Other protons may either be absorbed by the energy degrader ordiverted from the trajectory of the proton beam, no longer forming partof the transmitted proton beam and thereby reducing the flux of thetransmitted proton beam. An energy degrader may include, for example,carbon, plastics, beryllium, metals such as copper or lead, or anymaterial that is effective at reducing the energy or flux of the protonbeam. An energy degrader may also consist of any shape effective atreducing the energy or flux of the proton beam, including a wedge, adouble wedge separated by a gap (which may be filled with air or anothermaterial), a cylinder, a rectangle, or any other material orconfiguration capable of degrading the beam.

Those having ordinary skill in the art will recognize that the protonbeam filter configurations described above are only illustrative, andthat other configurations are contemplated consistent embodimentsdescribed herein.

In accordance with the present disclosure, a system for treating atreatment volume with protons may include a proton source. As used inthe present disclosure, a proton source may refer to any material,system or subsystem that has releasable protons or that is capable ofreleasing protons. A proton source may be configured to provide a protonbeam having a plurality of proton energies within a proton energyspread.

Further, in accordance with the present disclosure, a system fortreating a treatment volume with protons may include at least oneprocessor configured to control a relative movement between a protonbeam and a treatment volume in two dimensions of a three-dimensionalcoordinate system. The at least one processor may, for example, includeany of the processors described above. In some embodiments, a processormay be configured to control a proton energy spread to adjust a depth ofthe treatment volume in the third dimension of the three-dimensionalcoordinate system while maintaining substantially fixed coordinates inthe other two dimensions. For example, a third dimension of athree-dimensional coordinate system may refer to an approximatedirection of a proton beam trajectory, and the other two dimensionsrefer to the plane orthogonal to the third dimension.

Controlling a relative movement between a proton beam and a treatmentvolume in two dimensions of a three-dimensional coordinate system may beachieved in numerous ways. For example controlling relative movementbetween the proton beam and the treatment volume may be achieved byrotating a gantry. Alternatively or additionally, controlling relativemovement between the proton beam and a treatment volume may be achievedby directing a proton beam with an electromagnet and/or moving a patientsupport platform.

Likewise, controlling an energy spread and distribution or protons maybe achieved in a variety of ways. In accordance with the presentdisclosure, controlling energy spread may be achieved, for example, viaone or more of a magnetic analyzer, a time-of-flight control unit, andan energy degrader.

System 300 may be configured to vary of one or more properties of protonbeam 318 as others remain substantially fixed. In some embodiments, suchvariation may be achieved via feedback, such as described above inrelation to process 1100. For example, control system 314 may hold aflux of proton beam 318 substantially constant while independentlyadjusting an energy of proton beam 318, or hold the energy of protonbeam 318 substantially constant while independently adjusting its flux.Such independent adjustment may not be feasible in accelerator-basedsystems because of their large sizes and slow response times. Thesystems and methods disclosed herein, however, may achieve independentenergy and flux control by coupling feedback (as described above) withthe adjustable components of system 300 (also described above) toreconfigure properties of electromagnetic radiation beam 316 and thelaser-target interaction, thereby adjusting the energy and flux ofproton beam 318 separately. Thus, precise treatment may be deliveredmore quickly than traditional systems, reducing time spent by patientsin treatment and increasing patient throughput. Further, treatments canbe provided more accurately and with less damage to healthy tissue. Asan alternative, the systems and methods disclosed herein may achievesimultaneous energy and flux control by coupling feedback (as describedabove) with the adjustable components of system 300 (also describedabove) to reconfigure properties of electromagnetic radiation beam 316and the laser-target interaction, thereby adjusting the energy and fluxof proton beam 318 together.

In an embodiment, the energy and flux of proton beam 318 may be adjustedaccording to the intensity of electromagnetic radiation beam 316, thelocation of electromagnetic radiation beam on ion-generating target 304,the temporal profile of electromagnetic radiation beam 316, the spatialprofile of radiation beam 316, the settings and choice of proton beamadjustment component(s) 308. As an example, the energy of proton beam318 may be proportional to the intensity of electromagnetic radiationbeam 316, and the flux of proton beam 318 may be proportional to theenergy of electromagnetic radiation beam 316. This can be expressed bythe following relationships:

$\begin{matrix}{{{\left. E_{p} \right.\sim I_{L}} = \frac{E_{L}}{\Delta\;{\tau \cdot A}}}{and}} & (1) \\{\left. \varnothing_{p} \right.\sim E_{L}} & (2)\end{matrix}$in which I_(L) is the intensity of electromagnetic radiation beam 316,E_(L) is the intensity of electromagnetic radiation beam 316, Arepresents the spatial profile (e.g., a spot size) of electromagneticradiation beam 316, Δτ represents the temporal profile (e.g., pulseduration) of electromagnetic radiation beam 316, E_(p) is the energy ofproton beam 318, and Ø_(p) is the flux of proton beam 318. Accordingly,the energy of proton beam 318 may be held substantially constant whilethe flux of proton beam 318 varies, and vice versa, by properlyadjusting one or more of the energy, spatial profile, and temporalprofile of electromagnetic radiation beam 316. For example, to alterproton energy of proton beam 318 without changing proton flux, theenergy of electromagnetic radiation beam 316 may be held constant atabout 1 MeV while changing pulse duration and/or spot size ation-generating target 304.

Alternatively or additionally, the energy and flux of proton beam 318may be independently varied, for example, by choosing or adjustingproton beam adjustment component(s) 308 as appropriate. For example,this may be achieved by using one of the filtering systems and methodsdescribed above with respect to FIG. 13 or by using one or more energydegraders, for example.

When independently adjusting the flux of proton beam 318, the usablevariation in the energy of proton beam 318 may be as large as ±25% ormore where proton beam 318 is initially formed, and system 300 may becapable of reducing such fluctuations to about ±5% or less further downthe beam line. Similarly, when independently adjusting the energy ofproton beam 318, the usable variation in the flux of proton beam 318 maybe as large as ±25% or more where proton beam 318 is initially formed,and system 300 may be capable of reducing such fluctuations to about ±5%or less further down the beam line.

As an alternative to independently adjusting the energy and flux ofproton beam 318, the energy and flux of proton beam 318 may besimultaneously varied, for example, by choosing or adjusting proton beamadjustment component(s) 308 as appropriate. For example, this may beachieved by using one of the filtering systems and methods describedabove with respect to FIG. 13 or by using one or more energy degraders,for example.

Because process variables may fluctuate during operation, independentvariance of the energy and flux of proton beam 318 benefitssignificantly from the feedback adjustments described above with respectto FIG. 11. For example, as the detected laser-target interactionproperty varies in step 1108 during operation, control system 314 mayautomatically adjusts system 300 accordingly at step 1104 via feedbacksignals determined at step 1110.

System 300 may be configured to employ such variation of one or moreproperties of proton beam 318 while holding other properties of protonbeam 318 fixed in a process for systematic treatment of a treatmentvolume. FIG. 14 depicts an example of a process 1400 for such systematictreatment. At step 1402, control system 314 may position proton beam(e.g., beam 318) relative to the treatment volume in two dimensions of athree dimensional coordinate system. For example, the third dimensionmay be defined by the trajectory of the proton beam as it exits a gantry(e.g., gantry 310), and the two dimensions of the three dimensionalcoordinate system may be defined by the plane normal to the trajectoryof proton beam 318 as it exits gantry 310. Relative movement betweenproton beam 318 and the treatment volume in the two dimensions may becontrolled by one or more components of system 300. For example,relative movement may be controlled by any combination of one or moremotors and/or magnets associated with gantry 310 and/or one or moremotors associated with patient support platform 312. More specifically,control system 314 may be configured to control relative movementbetween proton beam 318 and a treatment volume by controlling one ormore of a rotation of gantry 310, an adjustment of scanning magnets 710,and a repositioning of patient support platform 312.

At step 1404, control system (e.g., system 314) may be configured tocontrol a relative movement between the proton beam and the treatmentvolume in a third dimension of the three-dimensional coordinate system.Control system 314 may be configured to control such relative movementin the third dimension while maintaining substantially fixed coordinatesin the other two dimensions. For example, control system 314 may controlproton energies to adjust a depth of the treatment while leaving theposition of proton beam 318 in the other two dimensions fixed.Controlling the proton energies at step 1404 may be achieved via one ormore of the techniques described above (with or without reference to theparticular structure described above). For example, at least one of theenergy, temporal profile, and spatial profile of electromagneticradiation beam 316 may be adjusted in accordance with equation 1 above,a proton energy selection as in FIGS. 12 and 13 may be used, and/or oneor more of a magnetic analyzer, a time-of-flight control unit, and anenergy degrader may be used.

An example of step 1404 is shown in FIGS. 15A, 15B, and 15C, whichdepict proton beam 318 penetrating skin 1502 of a patient 1504, toprovide treatment to a treatment volume 1506. FIGS. 15A, 15B, and 15Cmay represent a sequence of locations of treatment consistent with thedisclosed embodiments. System 300 may be configured to treat an area1508, shown in FIG. 15A, of a greater distance in the third dimension(i.e. further from patient 1504's skin 1502) before treating an area1510 by reducing the energy of proton beam 318, as shown in FIG. 15B,and then treating an area 1512, shown in FIG. 15C, by further reducingthe energy of proton beam 318. Alternatively, the sequence may bereversed, treating area 1512 of FIG. 15C, then increasing the energy ofproton beam 318 to treat area 1510 of FIG. 15B, then further increasingthe energy of proton beam 318 to treat area 1508 of FIG. 15A.

Additional locations of treatment may be included at step 1404 before,after, or intermediate to the areas 1508, 1510, and 1512 shown in FIGS.15A, 15B, and 15C. Control system 314 may also be configured to optimizetreatment to take into account effects of a particular sequence. Forexample, protons passing through treatment volume 1506 that are intendedto treat area 1508 (i.e., as shown in FIG. 15A) may provide somecollateral treatment to areas 1510 and 1512 before reaching 1508.Control system 314 may account for collateral doses administered toareas 1510 and 1512 by adjusting dosages in a patient's treatment planaccordingly. For example, control system 314 may be configured tointegrate all of the collateral doses that will be delivered to areas1510 and 1512 while directly treating other areas, such as area 1508,and to subtract those collateral doses from the direct dose appropriateto treat areas 1510 and 1512. Thus, a more accurate treatment can beachieved.

At step 1406, a control system (e.g., control system 314) may determinewhether another position requires treatment or whether treatment iscomplete. If treatment is complete (step 1006; YES), process 1400 mayend. If treatment is not complete (step 1006; NO), process 1000 mayreturn to step 1002, repositioning proton beam 318 relative to the twodimensions, as shown in FIG. 15D, and repeating the process of scanningthe depth in the third dimension by varying the energy of proton beam318.

While illustrative embodiments have been described herein, the scopethereof includes any and all embodiments having equivalent elements,modifications, omissions, combinations (e.g., of aspects across variousembodiments), adaptations and/or alterations as would be appreciated bythose in the art based on the present disclosure. For example, thenumber and orientation of components shown in the exemplary systems maybe modified. Further, with respect to the exemplary methods illustratedin the attached drawings, the order and sequence of steps may bemodified, and steps may be added or deleted.

Aspects of the invention may include a system for generating a protonbeam, the system comprising an interaction chamber configured to supportan ion-generating target; an electromagnetic radiation source configuredto provide an electromagnetic radiation beam; one or more opticscomponents configured to direct the electromagnetic radiation beam atthe ion-generating target to thereby cause a resultant proton beam; adetector configured to measure at least one laser-target interactionproperty; and one or more processors configured to produce a feedbacksignal based on the at least one laser-target interaction propertymeasured by the detector and to alter the proton beam by adjusting atleast one of the electromagnetic radiation source, the one or moreoptics component, and at least one of a relative position andorientation of the electromagnetic radiation beam to the ion-generatingtarget.

The laser-target interaction property may include a proton beamproperty, such as, for example, a proton beam energy and/or a protonbeam flux, which may include a secondary electron emission property. Asanother example, the laser-target interaction property may include anx-ray emission property.

The electromagnetic radiation source may be configured to provide apulsed electromagnetic radiation beam and to thereby cause a pulsedproton beam.

The interaction chamber may include a target stage for supporting theion-generating target, and the one or more processors may be furtherconfigured to cause relative movement between the target stage and theelectromagnetic radiation beam.

The structure of the ion-generating target may be determined, at leastin part, based upon a generated feedback signal generated from ameasured laser-target interaction property.

The laser-target interaction property may include a proton beam energyand/or a proton beam flux.

In response to the feedback signal, the at least one processor may beconfigured to cause the electromagnetic radiation source to alter anenergy of the electromagnetic radiation beam, a temporal profile of theelectromagnetic radiation beam, and/or a spatial of the electromagneticradiation beam (e.g., a spot size of the electromagnetic radiationbeam).

In response to the feedback signal, the at least one processor may beconfigured to cause the one or more optics components to alter an energyof the electromagnetic radiation beam, a temporal profile of theelectromagnetic radiation beam, and/or a spatial of the electromagneticradiation beam (e.g., a spot size of the electromagnetic radiationbeam).

The electromagnetic radiation source may be configured to alter atemporal profile of the electromagnetic radiation beam in response tothe feedback signal, and/or may also be configured to generate at leasta main pulse and a pre-pulse. The at least one processor may beconfigured to cause the electromagnetic radiation source to alter acontrast ratio of the pre-pulse to the main pulse in response to thefeedback signal.

The at least one processor may be configured to cause a motor to alterthe relative orientation between the electromagnetic radiation beam andthe ion-generating target in response to the feedback signal.

Aspects of the invention may also include a system for generating aproton beam, the system comprising an interaction chamber configured tosupport an ion-generating target; an electromagnetic radiation sourceconfigured to provide an electromagnetic radiation beam; an adaptivemirror configured to direct the electromagnetic radiation beam at theion-generating target in the interaction chamber to thereby generate aproton beam; and at least one processor configured to control theadaptive mirror so as to adjust at least one of a spatial profile of theelectromagnetic radiation beam and at least one of a relative positionand orientation between the electromagnetic radiation beam and theion-generating target.

The adaptive mirror may be configured to direct the electromagneticradiation beam by at least one of adjusting a focus of theelectromagnetic radiation beam, diverting the electromagnetic radiationbeam, and scanning the electromagnetic radiation beam. The adaptivemirror may also be configured to raster the electromagnetic radiationbeam over the ion-generating target. The adaptive mirror may include aplurality of facets, each of the plurality of facets being independentlycontrollable by digital logic circuitry. The adaptive mirror may includea laser pulse focused onto an anti-reflective coated substrate, one orboth of the laser pulse and anti-reflective coated substrate beingcontrollable by a digital logic circuitry.

The at least one processor may be configured to cause the adaptivemirror to direct the electromagnetic radiation beam at theion-generating target in response to a feedback signal, and/or to causethe adaptive mirror to direct the electromagnetic radiation beam atpredetermined locations on a surface of the ion-generating target. Asurface of the ion-generating target may include a patterned array,and/or a plurality of ion-generating structures substantially orientedalong a common axis. Alternatively or additionally, a surface of theion-generating target may include one or more knife edges.

The specification and claims may refer to elements in the singular, suchas “a processor” or “a detector.” It is to be understood that thissyntax is intended to be inclusive of multiple of such elements. Thatis, a particular function may be split over multiple processors locatedon a same board or system, or located remotely on another board or inanother system. It is to be understood that reference to a processor isto be interpreted as “at least one processor,” meaning that the functionrecited may occur across multiple processors and still be consideredwithin the scope of the disclosure and claims. The same is true fordetectors and other elements described or referenced in the singularthroughout the specification and claims.

Moreover, the foregoing description has been presented for purposes ofillustration. It is not exhaustive and is not limiting to the preciseforms or embodiments disclosed. Modifications and adaptations will beapparent to those skilled in the art from consideration of thespecification and practice of the disclosed embodiments. For example,where generation of protons is described above with respect to a laserstriking an ion-generating target, other proton generation processes maybe used, such as a radio-frequency coupling. Further, while somedescription above relates to use of protons in medicine as aradiotherapy treatment, systems and methods described herein may be usedin other applications of a proton beam and in applications involvingother ions than protons.

The claims are to be interpreted broadly based on the language employedin the claims and not limited to examples described in the presentspecification, which examples are to be construed as non-exclusive.Further, the steps of the disclosed methods may be modified in anymanner, including by reordering steps and/or inserting or deletingsteps.

The invention claimed is:
 1. A system for generating a proton beam, thesystem comprising: an interaction chamber configured to support anion-generating target; an electromagnetic radiation source configured toprovide an electromagnetic radiation beam; one or more optics componentsconfigured to direct the electromagnetic radiation beam at theion-generating target to thereby cause a resultant proton beam; adetector configured to measure at least one laser-target interactionproperty; and at least one processor configured to: receive a feedbacksignal based on the at least one laser-target interaction propertymeasured by the detector, wherein the feedback signal is indicative of arelationship between the proton beam and the electromagnetic radiationbeam; and based on the received feedback signal, alter the proton beamby adjusting an item among at least one of the following: (A) theelectromagnetic radiation source, (B) the one or more optics components,(C) at least one of a relative position and orientation of theelectromagnetic radiation beam to the ion-generating target; whereinaltering the proton beam includes altering a temporal profile of theelectromagnetic radiation beam based on the relationship between theproton beam and the electromagnetic radiation beam as indicated in thereceived feedback signal and by altering a chirp of the electromagneticradiation beam.
 2. The system for generating a proton beam in claim 1,wherein the laser-target interaction property includes a proton beamproperty.
 3. The system for generating a proton beam in claim 1, whereinthe laser-target interaction property includes an x-ray emissionproperty.
 4. The system for generating a proton beam in claim 1, whereinthe laser-target interaction property includes an energy spectrum ofelectromagnetic radiation.
 5. The system for generating a proton beam inclaim 1, wherein the interaction chamber includes a target stage forsupporting the ion-generating target, and the at least one processor isfurther configured to cause relative movement between the target stageand the electromagnetic radiation beam.
 6. The system for generating aproton beam in claim 2, wherein the proton beam property includes aproton beam energy.
 7. The system for generating a proton beam in claim2, wherein the proton beam property includes a proton beam flux.
 8. Thesystem for generating a proton beam in claim 1, wherein theelectromagnetic radiation source is configured to generate a main pulseand a pre-pulse, and the at least one processor is configured to causethe electromagnetic radiation source to alter a contrast ratio of thepre-pulse to the main pulse based on the relationship between the protonbeam and the electromagnetic radiation beam as indicated in the receivedfeedback signal.
 9. The system for generating a proton beam in claim 1,wherein the at least one processor is configured to cause theelectromagnetic radiation source to alter an energy of theelectromagnetic radiation beam based on the relationship between theproton beam and the electromagnetic radiation beam as indicated in thereceived feedback signal.
 10. The system for generating a proton beam inclaim 1, wherein the at least one processor is configured to cause theelectromagnetic radiation source to alter a spatial profile of theelectromagnetic radiation beam based on the relationship between theproton beam and the electromagnetic radiation beam as indicated in thereceived feedback signal.
 11. The system for generating a proton beam inclaim 1, wherein the at least one processor is configured to cause theone or more optics components to alter a spot size of theelectromagnetic radiation beam based on the relationship between theproton beam and the electromagnetic radiation beam as indicated in thereceived feedback signal.
 12. The system for generating a proton beam inclaim 1, wherein the at least one processor is configured to cause amotor to alter the relative orientation between the electromagneticradiation beam and the ion-generating target based on the relationshipbetween the proton beam and the electromagnetic radiation beam asindicated in the received feedback signal.
 13. The system for generatinga proton beam in claim 1, wherein the at least one processor isconfigured to alter the temporal profile of the electromagneticradiation beam by altering a timing of one or more laser pump sources.14. The system for generating a proton beam in claim 1, wherein theelectromagnetic radiation source is configured to generate a main pulseand a pre-pulse, and the at least one processor is configured control atiming of the pre-pulse based on the relationship between the protonbeam and the electromagnetic radiation beam as indicated in the receivedfeedback signal.
 15. A system for generating a proton beam, the systemcomprising: an interaction chamber configured to support anion-generating target; an electromagnetic radiation source configured toprovide an electromagnetic radiation beam; one or more optics componentsconfigured to direct the electromagnetic radiation beam at theion-generating target to thereby cause a resultant proton beam; adetector configured to measure at least one laser-target interactionproperty, wherein the laser-target interaction property includes asecondary electron emission property; and at least one processorconfigured to: receive a feedback signal based on the at least onelaser-target interaction property measured by the detector, wherein thefeedback signal is indicative of a relationship between the proton beamand the electromagnetic radiation beam; and based on the receivedfeedback signal, alter the proton beam by adjusting an item among atleast one of the following: (A) the electromagnetic radiation source,(B) the one or more optics components, (C) at least one of a relativeposition and orientation of the electromagnetic radiation beam to theion-generating target.
 16. A method for generating a proton beam, themethod comprising: producing an electromagnetic radiation beam;directing the electromagnetic radiation beam at an ion-generating targetto thereby cause a resultant proton beam; measuring at least onelaser-target interaction property with a detector; receiving a feedbacksignal based on the at least one laser-target interaction propertymeasured by the detector, wherein the feedback signal is indicative of arelationship between the proton beam and the electromagnetic radiationbeam; and based on the received feedback signal, altering the protonbeam by adjusting an item among at least one of the following: (A) theelectromagnetic radiation source, (B) the one or more optics component,(C) at least one of a relative position and orientation of theelectromagnetic radiation beam to the ion-generating target; whereinaltering the proton beam includes altering a temporal profile of theelectromagnetic radiation beam based on the relationship between theproton beam and the electromagnetic radiation beam as indicated in thereceived feedback signal by altering a timing of one or more laser pumpsources.
 17. The method of claim 16, wherein measuring the at least onelaser-target interaction property includes measuring a member of atleast one of the following categories: (A) a proton beam property, (B) asecondary electron emission property, (C) an x-ray emission property,(D) an energy spectrum of electromagnetic radiation.
 18. The method ofclaim 16, wherein altering the temporal profile of the electromagneticradiation beam by is achieved by altering a chirp of the electromagneticradiation beam.